Interconnect assembly

ABSTRACT

An interconnect assembly. The interconnect assembly includes a trace that includes a plurality of electrically conductive portions. The plurality of electrically conductive portions is configured both to collect current from a first solar cell and to interconnect electrically to a second solar cell. In addition, the plurality of electrically conductive portions is configured such that solar-cell efficiency is substantially undiminished in an event that any one of the plurality of electrically conductive portions is conductively impaired.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.12/052,476, filed Mar. 20, 2008, entitled INTERCONNECT ASSEMBLY, nowpending. This prior application is incorporated herein by reference inits entirety and for all purposes.

TECHNICAL FIELD

Embodiments of the present invention relate generally to the field ofphotovoltaic technology.

BACKGROUND

In the drive for renewable sources of energy, photovoltaic technologyhas assumed a preeminent position as a cheap renewable source of cleanenergy. In particular, solar cells based on the compound semiconductorcopper indium gallium diselenide (CIGS) used as an absorber layer offergreat promise for thin-film solar cells having high efficiency and lowcost. Of comparable importance to the technology used to fabricatethin-film solar cells themselves, is the technology used to collectcurrent from the solar cells and to interconnect one solar cell toanother to form a solar-cell module.

Just as the efficiency of thin-film solar cells is affected by parasiticseries resistances, solar-cell modules fabricated from arrays of suchthin-film solar cells are also impacted by parasitic series resistances.A significant challenge is the development of solar-cell, currentcollection and interconnection schemes that minimize the effects of suchparasitic resistances. Moreover, the reliability of solar-cell modulesbased on such schemes is equally important as it determines the usefullife of the solar-cell module and therefore its cost effectiveness andviability as a reliable alternative source of energy.

SUMMARY

Embodiments of the present invention include an interconnect assembly.The interconnect assembly includes a trace that includes a plurality ofelectrically conductive portions. The plurality of electricallyconductive portions is configured both to collect current from a firstsolar cell and to interconnect electrically to a second solar cell. Inaddition, the plurality of electrically conductive portions isconfigured such that solar-cell efficiency is substantially undiminishedin an event that any one of the plurality of electrically conductiveportions is conductively impaired.

DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthis specification, illustrate embodiments of the invention and,together with the description, serve to explain the embodiments of theinvention:

FIG. 1A is a cross-sectional elevation view of a layer structure of asolar cell, in accordance with an embodiment of the present invention.

FIG. 1B is a schematic diagram of a model circuit of a solar cell,electrically connected to a load, in accordance with an embodiment ofthe present invention.

FIG. 2 is a schematic diagram of a model circuit of a solar-cell module,electrically connected to a load, that shows the interconnection ofsolar cells in the solar-cell module, in accordance with an embodimentof the present invention.

FIG. 3 is a schematic diagram of a model circuit of a solar-cell module,electrically connected to a load, that details model circuits ofinterconnect assemblies, in accordance with an embodiment of the presentinvention.

FIG. 4A is a schematic diagram of a model circuit of an interconnectassembly for connecting two solar cells of a solar-cell module, inaccordance with an embodiment of the present invention.

FIG. 4B is a plan view of the interconnect assembly of FIG. 4A thatshows the physical interconnection of two solar cells in the solar-cellmodule, in accordance with an embodiment of the present invention.

FIG. 4C is a cross-sectional, elevation view of the interconnectassembly of FIG. 4B that shows the physical interconnection of two solarcells in the solar-cell module, in accordance with an embodiment of thepresent invention.

FIG. 4D is a cross-sectional, elevation view of an alternativeinterconnect assembly for FIG. 4B that shows an edge-conforminginterconnect assembly for the physical interconnection of two solarcells in the solar-cell module, in accordance with an embodiment of thepresent invention.

FIG. 4E is a cross-sectional, elevation view of an alternativeinterconnect assembly for FIG. 4B that shows a shingled-solar-cellarrangement for the physical interconnection of two solar cells in thesolar-cell module, in accordance with an embodiment of the presentinvention.

FIG. 4F is a plan view of an alternative interconnect assembly for FIG.4A that shows the physical interconnection of two solar cells in thesolar-cell module, in accordance with an embodiment of the presentinvention.

FIG. 5A is a plan view of the combined applicable carrier film,interconnect assembly that shows the physical arrangement of a tracewith respect to a top carrier film and a bottom carrier film in thecombined applicable carrier film, interconnect assembly, in accordancewith an embodiment of the present invention.

FIG. 5B is a cross-sectional, elevation view of the combined applicablecarrier film, interconnect assembly of FIG. 5A that shows the physicalarrangement of a trace with respect to a top carrier film in thecombined applicable carrier film, interconnect assembly prior todisposition on a solar cell, in accordance with an embodiment of thepresent invention.

FIG. 5C is a cross-sectional, elevation view of the interconnectassembly of FIG. 5B that shows the physical arrangement of a trace withrespect to a top carrier film in the combined applicable carrier film,interconnect assembly after disposition on a solar cell, in accordancewith an embodiment of the present invention.

FIG. 6A is a plan view of an integrated busbar-solar-cell-currentcollector that shows the physical interconnection of a terminating solarcell with a terminating busbar in the integratedbusbar-solar-cell-current collector, in accordance with an embodiment ofthe present invention.

FIG. 6B is a cross-sectional, elevation view of the integratedbusbar-solar-cell-current collector of FIG. 6A that shows the physicalinterconnection of the terminating solar cell with the terminatingbusbar in the integrated busbar-solar-cell-current collector, inaccordance with an embodiment of the present invention.

FIG. 7A is a combined cross-sectional elevation and perspective view ofa roll-to-roll, interconnect-assembly fabricator for fabricating theinterconnect assembly from a first roll of top carrier film and from adispenser of conductive-trace material, in accordance with an embodimentof the present invention.

FIG. 7B is a combined cross-sectional elevation and perspective view ofa roll-to-roll, laminated-interconnect-assembly for fabricating alaminated-interconnect assembly from the first roll of top carrier film,from a second roll of bottom carrier film and from the dispenser ofconductive-trace material, in accordance with an embodiment of thepresent invention.

FIG. 8 is flow chart illustrating a method for roll-to-roll fabricationof an interconnect assembly, in accordance with an embodiment of thepresent invention.

FIG. 9 is flow chart illustrating a method for interconnecting two solarcells, in accordance with an embodiment of the present invention.

The drawings referred to in this description should not be understood asbeing drawn to scale except if specifically noted.

DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the various embodiments of thepresent invention. While the invention will be described in conjunctionwith the various embodiments, it will be understood that they are notintended to limit the invention to these embodiments. On the contrary,the invention is intended to cover alternatives, modifications andequivalents, which may be included within the spirit and scope of theinvention as defined by the appended claims.

Furthermore, in the following description of embodiments of the presentinvention, numerous specific details are set forth in order to provide athorough understanding of the present invention. However, it should beappreciated that embodiments of the present invention may be practicedwithout these specific details. In other instances, well known methods,procedures, and components have not been described in detail as not tounnecessarily obscure embodiments of the present invention.

Physical Description of Embodiments of the Present Invention for anInterconnect Assembly

With reference to FIG. 1A, in accordance with an embodiment of thepresent invention, a cross-sectional elevation view of a layer structureof a solar cell 100A is shown. The solar cell 100A includes a metallicsubstrate 104. In accordance with an embodiment of the presentinvention, an absorber layer 112 is disposed on the metallic substrate104; the absorber layer 112 may include a layer of the material copperindium gallium diselenide (CIGS) having the chemical formulaCu(In_(1-x)Ga_(x))Se₂, where x may be a decimal less than one butgreater than zero that determines the relative amounts of theconstituents, indium, In, and gallium, Ga. Alternatively, semiconductorshaving the chalcopyrite crystal structure, for example, chemicallyhomologous compounds with the compound CIGS having the chalcopyritecrystal structure, in which alternative elemental constituents aresubstituted for Cu, In, Ga, and/or Se, may be used as the absorber layer112. Moreover, in embodiments of the present invention, it should benoted that semiconductors, such as silicon and cadmium telluride, aswell as other semiconductors, may be used as the absorber layer 112.

As shown, the absorber layer 112 includes a p-type portion 112 a and ann-type portion 112 b. As a result, a pn homojunction 112 c is producedin the absorber layer 112 that serves to separate charge carriers thatare created by light incident on the absorber layer 112. To facilitatethe efficient conversion of light energy to charge carriers in theabsorber layer 112, the composition of the p-type portion 112 a of theabsorber layer 112 may vary with depth to produce a graded band gap ofthe absorber layer 112. Alternatively, the absorber layer 112 mayinclude only a p-type chalcopyrite semiconductor layer, such as a CIGSmaterial layer, and a pn heterojunction may be produced between theabsorber layer 112 and an n-type layer, such as a metal oxide, metalsulfide or metal selenide, disposed on its top surface in place of then-type portion 112 b shown in FIG. 1A. However, embodiments of thepresent invention are not limited to pn junctions fabricated in themanner described above, but rather a generic pn junction produced eitheras a homojunction in a single semiconductor material, or alternatively aheterojunction between two different semiconductor materials, is withinthe spirit and scope of embodiments of the present invention. Moreover,in embodiments of the present invention, it should be noted thatsemiconductors, such as silicon and cadmium telluride, as well as othersemiconductors, may be used as the absorber layer 112.

In accordance with an embodiment of the present invention, on thesurface of the n-type portion 112 b of the absorber layer 112, one ormore transparent electrically conductive oxide (TCO) layers 116 aredisposed, for example, to provide a means for collection of current fromthe absorber layer 112 for conduction to an external load. As usedherein, it should be noted that the phrase “collection of current”refers to collecting current carriers of either sign, whether they bepositively charged holes or negatively charged electrons; for thestructure shown in FIG. 1A in which the TCO layer is disposed on then-type portion 112 b, the current carriers collected under normaloperating conditions are negatively charged electrons; but, embodimentsof the present invention apply, without limitation thereto, to solarcell configurations where a p-type layer is disposed on an n-typeabsorber layer, in which case the current carriers collected may bepositively charged holes. The TCO layer 116 may include zinc oxide, ZnO,or alternatively a doped conductive oxide, such as aluminum zinc oxide(AZO), AlZn_(1-x)O_(y), and indium tin oxide (ITO), In_(x)Sn_(1-x)O_(y),where the subscripts x and y indicate that the relative amount of theconstituents may be varied. Alternatively, the TCO layer 116 may becomposed of a plurality of conductive oxide layers. These TCO layermaterials may be sputtered directly from an oxide target, oralternatively the TCO layer may be reactively sputtered in an oxygenatmosphere from a metallic target, such as zinc, Zn, Al—Zn alloy, orIn—Sn alloy targets. For example, the zinc oxide may be deposited on theabsorber layer 112 by sputtering from a zinc-oxide-containing target;alternatively, the zinc oxide may be deposited from a zinc-containingtarget in a reactive oxygen atmosphere in a reactive-sputtering process.The reactive-sputtering process may provide a means for doping theabsorber layer 112 with an n-type dopant, such as zinc, Zn, or indium,In, to create a thin n-type portion 112 b, if the partial pressure ofoxygen is initially reduced during the initial stages of sputtering ametallic target, such as zinc, Zn, or indium, In, and the layerstructure of the solar cell 100A is subsequently annealed to allowinterdiffusion of the zinc, Zn, or indium, In, with CIGS material usedas the absorber layer 112. Alternatively, sputtering a compound target,such as a metal oxide, metal sulfide or metal selenide, may also be usedto provide the n-type layer, as described above, on the p-type portion112 a of the absorber layer 112.

With further reference to FIG. 1A, in accordance with the embodiment ofthe present invention, a conductive backing layer 108 may be disposedbetween the absorber layer 112 and the metallic substrate 104 to providea diffusion barrier between the absorber layer 112 and the metallicsubstrate 104. The conductive backing layer 108 may include molybdenum,Mo, or other suitable metallic layer having a low propensity forinterdiffusion with an absorber layer 112, such as one composed of CIGSmaterial, as well as a low diffusion coefficient for constituents of thesubstrate. Moreover, the conductive backing layer 108 may provide otherfunctions in addition to, or independent of, the diffusion-barrierfunction, for example, a light-reflecting function, for example, as alight-reflecting layer, to enhance the efficiency of the solar cell, aswell as other functions. The embodiments recited above for theconductive backing layer 108 should not be construed as limiting thefunction of the conductive backing layer 108 to only those recited, asother functions of the conductive backing layer 108 are within thespirit and scope of embodiments of the present invention, as well.

With reference now to FIG. 1B, in accordance with an embodiment of thepresent invention, a schematic diagram of a model circuit 100B of asolar cell that is electrically connected to a load is shown. The modelcircuit 100B of the solar cell includes a current source 158 thatgenerates a photocurrent, i_(L). As shown in FIG. 1A, the current source158 is such as to produce counterclockwise electrical current, orequivalently an clockwise electron-flow, flowing around each of theloops of the circuit shown; embodiments of the present invention alsoapply, without limitation thereto, to solar-cell circuits in which theelectrical current flows in a clockwise direction, or equivalentlyelectrons flow in a counterclockwise direction. The photocurrent, i_(L),is produced when a plurality of incident photons, light particles, ofwhich one example photon 154 with energy, hv, is shown, produceelectron-hole pairs in the absorber layer 112 and these electron-holepairs are separated by the pn homojunction 112 c, or in the alternative,by a pn heterojunction as described above. It should be appreciated thatthe energy, hv, of each incident photon of the plurality of photonsshould exceed the band-gap energy, E_(g), that separates the valenceband from the conduction band of the absorber layer 112 to produce suchelectron-hole pairs, which result in the photocurrent, i_(L).

The model circuit 100B of the solar cell further includes a diode 162,which corresponds to recombination currents, primarily at the pnhomojunction 112 c, that are shunted away from the connected load. Asshown in FIG. 1B, the diode is shown having a polarity consistent withelectrical current flowing counterclockwise, or equivalentlyelectron-flow clockwise, around the loops of the circuit shown;embodiments of the present invention apply, without limitation thereto,to a solar cell in which the diode of the model circuit has the oppositepolarity in which electrical current flows clockwise, or equivalentlyelectron-flow flows counterclockwise, around the loops of the circuitshown. In addition, the model circuit 100B of the solar cell includestwo parasitic resistances corresponding to a shunt resistor 166 withshunt resistance, R_(Sh), and to a series resistor 170 with seriesresistance, R_(S). The solar cell may be connected to a load representedby a load resistor 180 with load resistance, R_(L). Thus, the circuitelements of the solar cell include the current source 158, the diode 162and the shunt resistor 166 connected across the current source 158, andthe series resistor 170 connected in series with the load resistor 180across the current source 158, as shown. As the shunt resistor 166, likethe diode 162, are connected across the current source 158, these twocircuit elements are associated with internal electrical currents withinthe solar cell shunted away from useful application to the load. As theseries resistor 170 connected in series with the load resistor 180 areconnected across the current source 158, the series resistor 170 isassociated with internal resistance of the solar cell that limits theelectrical current to the load.

With further reference to FIG. 1B, it should be recognized that theshunt resistance may be associated with surface leakage currents thatfollow paths at free surfaces that cross the pn homojunction 112 c; freesurfaces are usually found at the edges of the solar cell along the sidewalls of the device that define its lateral dimensions; such freesurfaces may also be found at discontinuities in the absorber layer 112that extend past the pn homojunction 112 c. The shunt resistance mayalso be associated with shunt defects which may be present that shuntelectrical current away from the load. A small value of the shuntresistance, R_(Sh), is undesirable as it lowers the open circuitvoltage, V_(OC), of the solar cell, which directly affects theefficiency of the solar cell. Moreover, it should also be recognizedthat the series resistance, R_(S), is associated with: the contactresistance between the p-type portion 112 a and the conductive backinglayer 108, the bulk resistance of the p-type portion 112 a, the bulkresistance of the n-type portion 112 b, the contact resistance betweenthe n-type portion 112 b and TCO layer 116, and other components, suchas conductive leads, and connections in series with the load. Theselatter sources of series resistance, conductive leads, and connectionsin series with the load, are germane to embodiments of the presentinvention as interconnect assemblies, which is subsequently described. Alarge value of the series resistance, R_(S), is undesirable as it lowersthe short circuit current, I_(SC), of the solar cell, which alsodirectly affects the efficiency of the solar cell.

With reference now to FIG. 2, in accordance with an embodiment of thepresent invention, a schematic diagram of a model circuit 200 of asolar-cell module 204 that is coupled to a load is shown. The load isrepresented by a load resistor 208 with load resistance, R_(L), asshown. The solar-cell module 204 of the model circuit 200 includes aplurality of solar cells: a first solar cell 210 including a currentsource 210 a that generates a photocurrent, i_(L1), produced by examplephoton 214 with energy, hv₁, a diode 210 b and a shunt resistor 210 cwith shunt resistance, R_(Sh1); a second solar cell 230 including acurrent source 230 a that generates a photocurrent, i_(L2), produced byexample photon 234 with energy, hv₂, a diode 230 b and a shunt resistor230 c with shunt resistance, R_(Sh2); and, a terminating solar cell 260including a current source 260 a that generates a photocurrent, i_(L3),produced by example photon 264 with energy, hv_(n), a diode 260 b and ashunt resistor 260 c with shunt resistance, R_(Shn). Parasitic seriesinternal resistances of the respective solar cells 210, 230 and 260 havebeen omitted from the schematic diagram to simplify the discussion.Instead, series resistors with series resistances, R_(S1), R_(S2) andR_(Sn) are shown disposed in the solar-cell module 204 of the modelcircuit 200 connected in series with the solar cells 210, 230 and 260and the load resistor 208.

As shown in FIGS. 2 and 3, the current sources are such as to producecounterclockwise electrical current, or equivalently an clockwiseelectron-flow, flowing around each of the loops of the circuit shown;embodiments of the present invention also apply, without limitationthereto, to solar-cell circuits in which the electrical current flows ina clockwise direction, or equivalently electrons flow in acounterclockwise direction. Similarly, as shown in FIGS. 2 and 3, thediode is shown having a polarity consistent with electrical currentflowing counterclockwise, or equivalently electron-flow clockwise,around the loops of the circuit shown; embodiments of the presentinvention apply, without limitation thereto, to a solar cell in whichthe diode of the model circuit has the opposite polarity in whichelectrical current flows clockwise, or equivalently electron-flow flowscounterclockwise, around the loops of the circuit shown.

With further reference to FIG. 2, in accordance with an embodiment ofthe present invention, the series resistors with series resistancesR_(S1) and R_(S2) correspond to interconnect assemblies 220 and 240,respectively. Series resistor with series resistance, R_(S1),corresponding to interconnect assembly 220 is shown configured both tocollect current from the first solar cell 210 and to interconnectelectrically to the second solar cell 230. Series resistor with seriesresistance, R_(Sn), corresponds to an integrated solar-cell, currentcollector 270. The ellipsis 250 indicates additional solar cells andinterconnect assemblies (not shown) coupled in alternating pairs inseries in model circuit 200 that make up the solar-cell module 204.Also, in series with the solar cells 210, 230 and 260 are a first busbar284 and a terminating busbar 280 with series resistances R_(B1) andR_(B2), respectively, that carry the electrical current generated bysolar-cell module 204 to the load resistor 208. The series resistor withresistance R_(Sn), corresponding to the integrated solar-cell, currentcollector 270, and R_(B2), corresponding to the terminating busbar 280,in combination correspond to a integrated busbar-solar-cell-currentcollector 290 coupling the terminating solar cell 260 with the loadresistor 208. In addition, series resistor with resistance R_(S1),corresponding to interconnect assembly 220, and first solar cell 210 incombination correspond to a combined solar-cell, interconnect assembly294.

As shown in FIG. 2 and as used herein, it should be noted that thephrases “to collect current,” “collecting current” and “currentcollector” refer to collecting, transferring, and/or transmittingcurrent carriers of either sign, whether they be positively chargedholes or negatively charged electrons; for the structures shown in FIGS.1A-B, 2, 3, 4A-F, 5A-C and 6A-B, in which an interconnect assembly isdisposed above and electrically coupled to an n-type portion of thesolar cell, the current carriers collected under normal operatingconditions are negatively charged electrons. Moreover, embodiments ofthe present invention apply, without limitation thereto, to solar cellconfigurations where a p-type layer is disposed on an n-type absorberlayer, in which case the current carriers collected may be positivelycharged holes, as would be the case for solar cells modeled by diodesand current sources of opposite polarity to those of FIGS. 1A-B, 2, 3,4A-F, 5A-C and 6A-B. Therefore, in accordance with embodiments of thepresent invention, a current collector and associated interconnectassembly that collects current may, without limitation thereto, collect,transfer, and/or transmit charges associated with an electrical current,and/or charges associated with an electron-flow, as for either polarityof the diodes and current sources described herein, and thus for eitherconfiguration of a solar cell with an n-type layer disposed on andelectrically coupled to a p-type absorber layer or a p-type layerdisposed on and electrically coupled to an n-type absorber layer, aswell as other solar cell configurations.

With further reference to FIG. 2, in accordance with an embodiment ofthe present invention, the series resistances of the interconnectassemblies 220 and 240, integrated solar-cell, current collector 270,and the interconnect assemblies included in ellipsis 250 can have asubstantial net series resistance in the model circuit 200 of thesolar-cell module 204, unless the series resistances of the interconnectassemblies 220 and 240, integrated solar-cell, current collector 270,and the interconnect assemblies included in ellipsis 250 are made small.If a large plurality of solar cells are connected in series, the shortcircuit current of the solar-cell module, I_(SCM), may be reduced, whichalso directly affects the solar-cell-module efficiency analogous to themanner in which solar-cell efficiency is reduced by a parasitic seriesresistance, R_(S), as described above with reference to FIG. 1.Embodiments of the present invention provide for diminishing the seriesresistances of the interconnect assemblies 220 and 240, integratedsolar-cell, current collector 270, and the interconnect assembliesincluded in ellipsis 250.

With reference now to FIG. 3, in accordance with embodiments of thepresent invention, a schematic diagram of a model circuit 300 of asolar-cell module 304 is shown that illustrates embodiments of thepresent invention such that the series resistances of the interconnectassemblies 320 and 340, integrated solar-cell, current collector 370,and the interconnect assemblies included in ellipsis 350 are made small.The solar-cell module 304 is coupled to a load represented by a loadresistor 308 with load resistance, R_(L), as shown. The solar-cellmodule 304 of the model circuit 300 includes a plurality of solar cells:a first solar cell 310 including a current source 310 a that generates aphotocurrent, i_(L1), produced by example photon 314 with energy, hv₁, adiode 310 b and a shunt resistor 310 c with shunt resistance, R_(Sh1); asecond solar cell 330 including a current source 330 a that generates aphotocurrent, i_(L2), produced by example photon 334 with energy, hv₂, adiode 330 b and a shunt resistor 330 c with shunt resistance, R_(Sh2);and, a terminating solar cell 360 including a current source 360 a thatgenerates a photocurrent, i_(L3), produced by example photon 364 withenergy, hv_(n), a diode 360 b and a shunt resistor 360 c with shuntresistance, R_(Shn).

With further reference to FIG. 3, in accordance with an embodiment ofthe present invention, the interconnect assemblies 320 and 340 and theintegrated solar-cell, current collector 370, with respective equivalentseries resistances R_(S1), R_(S2) and R_(Sn) are shown disposed in thesolar-cell module 304 of the model circuit 300 connected in series withthe solar cells 310, 330 and 360 and the load resistor 308. The ellipsis350 indicates additional solar cells and interconnect assemblies (notshown) coupled in alternating pairs in series in model circuit 300 thatmake up the solar-cell module 304. Also, in series with the solar cells310, 330 and 360 are a first busbar 384 and a terminating busbar 380with series resistances R_(B1) and R_(B2), respectively, that carry theelectrical current generated by solar-cell module 304 to the loadresistor 308. The integrated solar-cell, current collector 370 withresistance R_(Sn), and the series resistor with series resistanceR_(B2), corresponding to the terminating busbar 380, in combinationcorrespond to an integrated busbar-solar-cell-current collector 390coupling the terminating solar cell 360 with the load resistor 308. Inaddition, interconnect assembly 320 with resistance, R_(S2), and solarcell 310 in combination correspond to a combined solar-cell,interconnect assembly 394.

With further reference to FIG. 3, in accordance with embodiments of thepresent invention, the interconnect assembly 320 includes a traceincluding a plurality of electrically conductive portions, identifiedwith resistors 320 a, 320 b, 320 c, and 320 m with respectiveresistances, r_(P11), r_(P12), r_(P13) and r_(P1m), and the ellipsis 320i indicating additional resistors (not shown). It should be noted thatalthough the plurality of electrically conductive portions of the traceare modeled here as discrete resistors the interconnection with solarcell 330 is considerably more complicated involving the distributedresistance in the TCO layer of the solar cell, which has been omittedfor the sake of elucidating functional features of embodiments of thepresent invention. Therefore, it should be understood that embodimentsof the present invention may also include, without limitation thereto,the effects of such distributed resistances on the trace. The pluralityof electrically conductive portions, without limitation thereto,identified with resistors 320 a, 320 b, 320 c, 320 i, and 320 m, areconfigured both to collect current from the first solar cell 310 and tointerconnect electrically to the second solar cell 330. The plurality ofelectrically conductive portions, identified with resistors 320 a, 320b, 320 c, 320 i, and 320 m, are configured such that uponinterconnecting the first solar cell 310 and the second solar cell 330the plurality of electrically conductive portions are connectedelectrically in parallel between the first solar cell 310 and the secondsolar cell 330.

Thus, in accordance with embodiments of the present invention, theplurality of electrically conductive portions is configured such thatequivalent series resistance, R_(S1), of the interconnect assembly 320including the parallel network of resistors 320 a, 320 b, 320 c, 320 i,and 320 m, is less than the resistance of any one resistor in theparallel network. Therefore, upon interconnecting the first solar cell310 with the second solar cell 330, the equivalent series resistance,R_(S1), of the interconnect assembly 320, is given approximately,omitting the effects of distributed resistances at the interconnectswith the first and second solar cells 310 and 330, by the formula for aplurality of resistors connected electrically in parallel, viz.R_(S1)=1/[Σ(1/r_(P1i))], where r_(P1i) is the resistance of the ithresistor in the parallel-resistor network, and the sum, Σ, is taken overall of the resistors in the network from i=1 to m. Hence, by connectingthe first solar cell 310 to the second solar cell 330, with theinterconnect assembly 320, the series resistance, R_(S1), of theinterconnect assembly 320 can be reduced lowering the effective seriesresistance between solar cells in the solar-cell module 304 improvingthe solar-cell-module efficiency.

Moreover, in accordance with embodiments of the present invention, theconfiguration of the plurality of electrically conductive portions dueto this parallel arrangement of electrically conductive portions betweenthe first solar cell 310 and the second solar cell 330 provides aredundancy of electrical current carrying capacity betweeninterconnected solar cells should one of the plurality of electricallyconductive portions become damaged, or its reliability become impaired.Thus, embodiments of the present invention provide that the plurality ofelectrically conductive portions is configured such that solar-cellefficiency is substantially undiminished in an event that any one of theplurality of electrically conductive portions is conductively impaired,because the loss of electrical current through any one electricallyconductive portion will be compensated for by the plurality of otherparallel electrically conductive portions coupling the first solar cell310 with the second solar cell 330. It should be noted that as usedherein the phrase, “substantially undiminished,” with respect tosolar-cell efficiency means that the solar-cell efficiency is notreduced below an acceptable level of productive performance.

With further reference to FIG. 3, in accordance with embodiments of thepresent invention, the interconnect assembly 340 includes a traceincluding a plurality of electrically conductive portions identifiedwith resistors 340 a, 340 b, 340 c, and 340 m with respectiveresistances, r_(P21), r_(P22) , r_(P23) and r_(P2m), and the ellipsis340 i indicating additional resistors (not shown). The plurality ofelectrically conductive portions, without limitation thereto, identifiedwith resistors 340 a, 340 b, 340 c, 340 i, and 340 m, are configuredboth to collect current from a first solar cell 330 and to interconnectelectrically to a second solar cell, in this case a next adjacent one ofthe plurality of solar cells represented by ellipsis 350. From thisexample, it should be clear that for embodiments of the presentinvention a first solar cell and a second solar cell refer, withoutlimitation thereto, to just two adjacent solar cells configured inseries in the solar-cell module, and need not be limited to a solar celllocated first in line of a series of solar cells in a solar-cell module,nor a solar cell located second in line of a series of solar cells in asolar-cell module. The resistors 340 a, 340 b, 340 c, 340 i, and 340 m,are configured such that upon interconnecting the first solar cell 330and the second solar cell, in this case the next adjacent solar cell ofthe plurality of solar cells represented by ellipsis 350, the resistors340 a, 340 b, 340 c, 340 i, and 340 m, are coupled electrically inparallel between the first solar cell 330 and the second solar cell, thenext adjacent solar cell of the plurality of solar cells represented byellipsis 350.

Thus, in accordance with embodiments of the present invention, theplurality of electrically conductive portions is configured such thatseries resistance, R_(S2), of the interconnect assembly 340 includingthe parallel network of resistors 340 a, 340 b, 340 c, 340 i, and 340 m,is less than the resistance of any one resistor in the network. Hence,the series resistance, R_(S2), of the interconnect assembly 340 can bereduced lowering the effective series resistance between solar cells inthe solar-cell module improving the solar-cell-module efficiency of thesolar-cell module 304. Moreover, the plurality of electricallyconductive portions, identified with resistors 340 a, 340 b, 340 c, 340i, and 340 m, may be configured such that solar-cell efficiency issubstantially undiminished in an event that any one of the plurality ofelectrically conductive portions is conductively impaired.

With further reference to FIG. 3, in accordance with embodiments of thepresent invention, the combined solar-cell, interconnect assembly 394includes the first solar cell 310 and the interconnect assembly 320; theinterconnect assembly 320 includes a trace disposed above a light-facingside of the first solar cell 310, the trace further including aplurality of electrically conductive portions, identified with resistors320 a, 320 b, 320 c, and 320 m with respective resistances, r_(P21),r_(P22), r_(P23) and r_(P2m), and the ellipsis 320 i indicatingadditional resistors (not shown). All electrically conductive portionsof the plurality of electrically conductive portions, without limitationthereto, identified with resistors 320 a, 320 b, 320 c, 320 i, and 320m, are configured to collect current from the first solar cell 310 andto interconnect electrically to the second solar cell 330. In addition,the plurality of electrically conductive portions, identified withresistors 320 a, 320 b, 320 c, 320 i, and 320 m, may be configured suchthat solar-cell efficiency is substantially undiminished in an eventthat any one of the plurality of electrically conductive portions isconductively impaired. Also, any of the plurality of electricallyconductive portions, identified with resistors 320 a, 320 b, 320 c, 320i, and 320 m, may be configured to interconnect electrically to thesecond solar cell 330.

With further reference to FIG. 3, in accordance with embodiments of thepresent invention, the integrated busbar-solar-cell-current collector390 includes the terminating busbar 380 and the integrated solar-cell,current collector 370. The integrated solar-cell, current collector 370includes a trace including a plurality of electrically conductiveportions, identified with resistors 370 a, 370 b, 370 l, and 370 m withrespective resistances, r_(Pn1), r_(Pn2) , r_(Pn1) and r_(Pnm), and theellipsis 370 i indicating additional resistors (not shown). Theplurality of electrically conductive portions, without limitationthereto, identified with resistors 370 a, 370 b, 370 i, 370 l and 370 m,are configured both to collect current from the first solar cell 310 andto interconnect electrically to the terminating busbar 380. Theresistors 370 a, 370 b, 370 i, 370 l and 370 m, are coupled electricallyin parallel between the terminating solar cell 360 and the terminatingbusbar 380 series resistor with series resistance, R_(B2). Thus, theplurality of electrically conductive portions is configured such thatseries resistance, R_(Sn), of the interconnect assembly 340 includingthe parallel network of resistors 370 a, 370 b, 370 i, 370 l and 370 m,is less than the resistance of any one resistor in the network.

In accordance with embodiments of the present invention, the integratedsolar-cell, current collector 370 includes a plurality of integratedpairs of electrically conductive, electrically parallel trace portions.Resistors 370 a, 370 b, 370 l and 370 m with respective resistances,r_(Pn1), r_(Pn2) , r_(Pn1) and r_(Pnm), and the ellipsis 370 iindicating additional resistors (not shown) form such a plurality ofintegrated pairs of electrically conductive, electrically parallel traceportions when suitably paired as adjacent pair units connectedelectrically together as an integral unit over the terminating solarcell 360. For example, one such pair of the plurality of integratedpairs of electrically conductive, electrically parallel trace portionsis pair of resistors 370 a and 370 b connected electrically together asan integral unit over the terminating solar cell 360, as shown. Theplurality of integrated pairs of electrically conductive, electricallyparallel trace portions are configured both to collect current from theterminating solar cell 360 and to interconnect electrically to theterminating busbar 380. Moreover, the plurality of integrated pairs ofelectrically conductive, electrically parallel trace portions isconfigured such that solar-cell efficiency is substantially undiminishedin an event that any one electrically conductive, electrically paralleltrace portion, for example, either one, but not both, of the resistors370 a and 370 b of the integral pair, of the plurality of integratedpairs of electrically conductive, electrically parallel trace portionsis conductively impaired.

With further reference to FIG. 3, in accordance with embodiments of thepresent invention, the solar-cell module 304 includes the first solarcell 310, at least the second solar cell 330 and the interconnectassembly 320 disposed above a light-facing side of an absorber layer ofthe first solar cell 310. The interconnect assembly 320 includes a tracecomprising a plurality of electrically conductive portions, identifiedwith resistors 320 a, 320 b, 320 c, and 320 m with respectiveresistances, r_(P11), r_(P12) , r_(P13) and r_(P1m), and the ellipsis320 i indicating additional resistors (not shown). The plurality ofelectrically conductive portions is configured both to collect currentfrom the first solar cell 310 and to interconnect electrically to thesecond solar cell 330. The plurality of electrically conductive portionsis configured such that solar-cell efficiency is substantiallyundiminished in an event that any one of the plurality of electricallyconductive portions is conductively impaired.

With reference now to FIGS. 4A, 4B and 4C, in accordance withembodiments of the present invention, a schematic diagram of a modelcircuit 400A of an interconnect assembly 420 connecting a first solarcell 410 to a second solar cell 430 of a solar-cell module 404 is shown.The interconnect assembly 420 includes a trace including a plurality ofelectrically conductive portions, identified with resistors 420 a, 420b, 420 c, and 420 m with respective resistances, r_(P11), r_(P12) ,r_(P13) and r_(P1m), and the ellipsis 420 i indicating additionalresistors (not shown). The plurality of electrically conductiveportions, without limitation thereto, identified with resistors 420 a,420 b, 420 c, 420 i, and 420 m, are configured both to collect currentfrom the first solar cell 410 and to interconnect electrically to thesecond solar cell 430. The plurality of electrically conductiveportions, identified with resistors 420 a, 420 b, 420 c, 420 i, and 420m, are configured such that, upon interconnecting the first solar cell410 and the second solar cell 430, the plurality of electricallyconductive portions are connected electrically in parallel between thefirst solar cell 410 and the second solar cell 430. The plurality ofelectrically conductive portions is configured such that equivalentseries resistance, R_(S1), of the interconnect assembly 420 includingthe parallel network of resistors 420 a, 420 b, 420 c, 420 i, and 420 m,is less than the resistance of any one resistor in the parallel network.Therefore, by connecting the first solar cell 410 to the second solarcell 430, with the interconnect assembly 420, the series resistance,R_(S1), of the interconnect assembly 420 can be reduced lowering theeffective series resistance between solar cells in the solar-cell module404 improving the solar-cell-module efficiency.

Moreover, in accordance with embodiments of the present invention, theconfiguration of the plurality of electrically conductive portions dueto this parallel arrangement of electrically conductive portions betweenthe first solar cell 410 and the second solar cell 430 provides aredundancy of electrical current carrying capacity betweeninterconnected solar cells should any one of the plurality ofelectrically conductive portions become damaged, or its reliabilitybecome impaired. Thus, embodiments of the present invention provide thatthe plurality of electrically conductive portions is configured suchthat solar-cell efficiency is substantially undiminished in an eventthat any one of the plurality of electrically conductive portions isconductively impaired, because the loss of electrical current throughany one electrically conductive portion will be compensated for by theplurality of the unimpaired parallel electrically conductive portionscoupling the first solar cell 410 with the second solar cell 430. Itshould be noted that as used herein the phrase, “substantiallyundiminished,” with respect to solar-cell efficiency means that thesolar-cell efficiency is not reduced below an acceptable level ofproductive performance. In addition, in accordance with embodiments ofthe present invention, the plurality of electrically conductive portionsmay be configured in pairs of electrically conductive portions, forexample, identified with resistors 420 a and 420 b. Thus, the pluralityof electrically conductive portions may be configured such thatsolar-cell efficiency is substantially undiminished even in an eventthat, in every pair of electrically conductive portions of the pluralityof electrically conductive portions, one electrically conductive portionof the pair is conductively impaired. In accordance with embodiments ofthe present invention, each member of a pair of electrically conductiveportions may be electrically equivalent to the other member of the pair,but need not be electrically equivalent to the other member of the pair,it only being necessary that in an event one member, a first member, ofthe pair becomes conductively impaired the other member, a secondmember, is configured such that solar-cell efficiency is substantiallyundiminished.

With further reference to FIGS. 4B and 4C, in accordance withembodiments of the present invention, a plan view 400B of theinterconnect assembly 420 of FIG. 4A is shown that details the physicalinterconnection of two solar cells 410 and 430 in the solar-cell module404. The solar-cell module 404 includes the first solar cell 410, atleast the second solar cell 430 and the interconnect assembly 420disposed above a light-facing side 416 of the absorber layer of thefirst solar cell 410. The interconnect assembly 420 includes a tracecomprising a plurality of electrically conductive portions 420 a, 420 b,420 c, 420 i and 420 m, previously identified herein with the resistors420 a, 420 b, 420 c, 420 i and 420 m described in FIG. 400A, where theellipsis of 420 i indicates additional electrically conductive portions(not shown). The plurality of electrically conductive portions 420 a,420 b, 420 c, 420 i and 420 m is configured both to collect current fromthe first solar cell 410 and to interconnect electrically to the secondsolar cell 430. The plurality of electrically conductive portions 420 a,420 b, 420 c, 420 i and 420 m is configured such that solar-cellefficiency is substantially undiminished in an event that any one of theplurality of electrically conductive portions 420 a, 420 b, 420 c, 420 iand 420 m is conductively impaired.

With further reference to FIG. 4B, in accordance with embodiments of thepresent invention, the detailed configuration of the plurality ofelectrically conductive portions 420 a, 420 b, 420 c, 420 i and 420 m isshown. The plurality of electrically conductive portions 420 a, 420 b,420 c, 420 i and 420 m further includes a first portion 420 a of theplurality of electrically conductive portions 420 a, 420 b, 420 c, 420 iand 420 m configured both to collect current from the first solar cell410 and to interconnect electrically to the second solar cell 430 and asecond portion 420 b of the plurality of electrically conductiveportions 420 a, 420 b, 420 c, 420 i and 420 m configured both to collectcurrent from the first solar cell 410 and to interconnect electricallyto the second solar cell 430. The first portion 420 a includes a firstend 420 p distal from the second solar cell 430. Also, the secondportion 420 b includes a second end 420 q distal from the second solarcell 430. The second portion 420 b is disposed proximately to the firstportion 420 a and electrically connected to the first portion 420 a suchthat the first distal end 420 p is electrically connected to the seconddistal end 420 q, for example, at first junction 420 r, or by a linkingportion, such that the second portion 420 b is configured electricallyin parallel to the first portion 420 a when configured to interconnectto the second solar cell 430.

With further reference to FIG. 4B, in accordance with embodiments of thepresent invention, the plurality of electrically conductive portions 420a, 420 b, 420 c, 420 i and 420 m may further include the second portion420 b including a third end 420 s distal from the first solar cell 410and a third portion 420 c of the plurality of electrically conductiveportions 420 a, 420 b, 420 c, 420 i and 420 m configured both to collectcurrent from the first solar cell 410 and to interconnect electricallyto the second solar cell 430. The third portion 420 c includes a fourthend 420 t distal from the first solar cell 410. The third portion 420 cis disposed proximately to the second portion 420 b and electricallyconnected to the second portion 420 b such that the third distal end 420s is electrically connected to the fourth distal end 420 t, for example,at second junction 420 u, or by a linking portion, such that the thirdportion 420 c is configured electrically in parallel to the secondportion 420 b when configured to interconnect with the first solar cell430.

With further reference to FIGS. 4B and 4C, in accordance withembodiments of the present invention, it should be noted that the natureof the parallel connection between electrically conductive portionsinterconnecting a first solar cell and a second solar cell is such that,for distal ends of electrically conductive portions not directly joinedtogether, without limitation thereto, the metallic substrate of a secondsolar cell and a TCO layer of the first solar cell may provide thenecessary electrical coupling. For example, distal ends 420 v and 420 sare electrically coupled through a low resistance connection through ametallic substrate 430 c of second solar cell 430. Similarly, forexample, distal ends 420 w and 420 q are electrically coupled throughthe low resistance connection through the TCO layer 410 b of first solarcell 410.

With further reference to FIG. 4B, in accordance with embodiments of thepresent invention, an open-circuit defect 440 is shown such that secondportion 420 b is conductively impaired. FIG. 4B illustrates the mannerin which the plurality of electrically conductive portions 420 a, 420 b,420 c, 420 i and 420 m is configured such that solar-cell efficiency issubstantially undiminished in an event that any one of the plurality ofelectrically conductive portions 420 a, 420 b, 420 c, 420 i and 420 m isconductively impaired, for example, second portion 420 b. An arrow 448indicates the nominal electron-flow through a third portion 420 c of theplurality of electrically conductive portions 420 a, 420 b, 420 c, 420 iand 420 m essentially unaffected by open-circuit defect 440. In theabsence of open-circuit defect 440, an electron-flow indicated by arrow448 would normally flow through any one electrically conductive portionof the plurality of electrically conductive portions 420 a, 420 b, 420c, 420 i and 420 m, in particular, second portion 420 b. However, whenthe open-circuit defect 440 is present, this electron-flow divides intotwo portions shown by arrows 442 and 444: arrow 442 corresponding tothat portion of the normal electron-flow flowing to the right along thesecond portion 420 b to the second solar cell 430, and arrow 444corresponding to that portion of the normal electron-flow flowing to theleft along the second portion 420 b to the first portion 420 a and thento the right along the first portion 420 a to the second solar cell 430.Thus, the net electron-flow represented by arrow 446 flowing to theright along the first portion 420 a is consequently larger than whatwould normally flow to the right along the first portion 420 a to thesecond solar cell 430 in the absence of the open-circuit defect 440.

It should be noted that open-circuit defect 440 is for illustrationpurposes only and that embodiments of the present invention compensatefor other types of defects in an electrically conductive portion, ingeneral, such as, without limitation to: a delamination of anelectrically conductive portion from the first solar cell 410, corrosionof an electrically conductive portion, and even complete loss of anelectrically conductive portion. In accordance with embodiments of thepresent invention, in the event a defect completely conductively impairsan electrically conductive portion, the physical spacing betweenadjacent electrically conductive portions, identified with double-headedarrow 449, may be chosen such that solar-cell efficiency issubstantially undiminished. Nevertheless, embodiments of the presentinvention embrace, without limitation thereto, other physical spacingsbetween adjacent electrically conductive portions in the event defectsare less severe than those causing a complete loss of one of theelectrically conductive portions.

With further reference to FIG. 4B, in accordance with embodiments of thepresent invention, the plurality of electrically conductive portions 420a, 420 b, 420 c, 420 i and 420 m may be connected electrically in seriesto form a single continuous electrically conductive line. Moreover, thetrace that includes the plurality of electrically conductive portions420 a, 420 b, 420 c, 420 i and 420 m may be disposed in a serpentinepattern such that the interconnect assembly 420 is configured to collectcurrent from the first solar cell 410 and to interconnect electricallyto the second solar cell 430, as shown.

With further reference to FIG. 4C, in accordance with embodiments of thepresent invention, a cross-sectional, elevation view 400C of theinterconnect assembly 420 is shown that further details the physicalinterconnection of two solar cells 410 and 430 in the solar-cell module404. Projections 474 and 478 of planes orthogonal to both of the viewsin FIGS. 4B and 4C, and coincident with the ends of the plurality ofelectrically conductive portions 420 a, 420 b, 420 c, 420 i and 420 mshow the correspondence between features of the plan view 400B of FIG.4B and features in the cross-sectional, elevation view 400C of FIG. 4C.Also, it should be noted that although the solar-cell module 404 isshown with separation 472 between the first solar cell 410 and thesecond solar cell 430, there need not be such separation 472 between thefirst solar cell 410 and the second solar cell 430. As shown in FIGS. 4Band 4C, a combined solar-cell, interconnect assembly 494 includes thefirst solar cell 410 and the interconnect assembly 420. The interconnectassembly 420 includes the trace disposed above the light-facing side 416of the first solar cell 410, the trace further including the pluralityof electrically conductive portions 420 a, 420 b, 420 c, 420 i and 420m. All electrically conductive portions of the plurality of electricallyconductive portions 420 a, 420 b, 420 c, 420 i and 420 m are configuredto collect current from the first solar cell 410 and to interconnectelectrically to the second solar cell 430. In addition, the plurality ofelectrically conductive portions 420 a, 420 b, 420 c, 420 i and 420 mmay be configured such that solar-cell efficiency is substantiallyundiminished in an event that any one of the plurality of electricallyconductive portions 420 a, 420 b, 420 c, 420 i and 420 m is conductivelyimpaired. Also, any of the plurality of electrically conductive portions420 a, 420 b, 420 c, 420 i and 420 m may be configured to interconnectelectrically to the second solar cell 430. The first solar cell 410 ofthe combined solar-cell, interconnect assembly 494 may include ametallic substrate 410 c and an absorber layer 410 a. The absorber layer410 a of the first solar cell 410 may include copper indium galliumdiselenide (CIGS). Alternatively, other semiconductors having thechalcopyrite crystal structure, for example, chemically homologouscompounds with the compound CIGS having the chalcopyrite crystalstructure, in which alternative elemental constituents are substitutedfor Cu, In, Ga, and/or Se, may be used as the absorber layer 410 a.Moreover, in embodiments of the present invention, it should be notedthat semiconductors, such as silicon and cadmium telluride, as well asother semiconductors, may be used as the absorber layer 410 a.

With further reference to FIG. 4C, in accordance with embodiments of thepresent invention, the plurality of electrically conductive portions 420a, 420 b, 420 c, 420 i and 420 m of the combined solar-cell,interconnect assembly 494 further includes the first portion 420 a ofthe plurality of electrically conductive portions 420 a, 420 b, 420 c,420 i and 420 m configured to collect current from the first solar cell410 and the second portion 420 b of the plurality of electricallyconductive portions 420 a, 420 b, 420 c, 420 i and 420 m configured tocollect current from the first solar cell 410. The first portion 420 aincludes the first end 420 p distal from an edge 414 of the first solarcell 410. The second portion 420 b includes the second end 420 q distalfrom the edge 414 of the first solar cell 410. The second portion 420 bis disposed proximately to the first portion 420 a and electricallyconnected to the first portion 420 a such that the first distal end 420p is electrically connected to the second distal end 420 q such that thesecond portion 420 b is configured electrically in parallel to the firstportion 420 a when configured to interconnect to the second solar cell430.

With further reference to FIG. 4C, in accordance with embodiments of thepresent invention, the interconnect assembly 420 further includes a topcarrier film 450. The top carrier film 450 includes a firstsubstantially transparent, electrically insulating layer coupled to thetrace and disposed above a top portion of the trace. The firstsubstantially transparent, electrically insulating layer allows forforming a short-circuit-preventing portion 454 at an edge 434 of thesecond solar cell 430. The first substantially transparent, electricallyinsulating layer allows for forming the short-circuit-preventing portion454 at the edge 434 of the second solar cell 430 to prevent the firstportion 420 a from short circuiting an absorber layer 430 a of thesecond solar cell 430 in the event that the first portion 420 a bucklesand rides up a side 432 of second solar cell 430. The edge 434 islocated at the intersection of the side 432 of the second solar cell 430and a back side 438 of the second solar cell 430 that couples with theplurality of electrically conductive portions 420 a, 420 b, 420 c, 420 iand 420 m, for example, first portion 420 a as shown. The second solarcell 430 may include the absorber layer 430 a, a TCO layer 430 b, andthe metallic substrate 430 c; a backing layer (not shown) may also bedisposed between the absorber layer 430 a and the metallic substrate 430c. Above a light-facing side 436 of the second solar cell 430, anintegrated busbar-solar-cell-current collector (not shown in FIG. 4C,but which is shown in FIGS. 6A and 6B) may be disposed and coupled tothe second solar cell 430 to provide interconnection with a load (notshown). Alternatively, above the light-facing side 436 of the secondsolar cell 430, another interconnect assembly (not shown) may bedisposed and coupled to the second solar cell 430 to provideinterconnection with additional solar-cells (not shown) in thesolar-cell module 404.

With further reference to FIG. 4C, in accordance with embodiments of thepresent invention, the interconnect assembly 420 further includes abottom carrier film 460. The bottom carrier film 460 may include asecond electrically insulating layer coupled to the trace and disposedbelow a bottom portion of the trace. Alternatively, The bottom carrierfilm 460 may include a carrier film selected from a group consisting ofa second electrically insulating layer, a structural plastic layer, anda metallic layer, and is coupled to the trace and is disposed below abottom portion of the trace. The second electrically insulating layerallows for forming an edge-protecting portion 464 at the edge 414 of thefirst solar cell 410. Alternatively, a supplementary isolation strip(not shown) of a third electrically insulating layer may be disposedbetween the bottom carrier film 460 and the first portion 420 a of theplurality of electrically conductive portions 420 a, 420 b, 420 c, 420 iand 420 m, or alternatively between the bottom carrier film 460 and theedge 414, to provide additional protection at the edge 414. Thesupplementary isolation strip may be as wide as 5 millimeters (mm) inthe direction of the double-headed arrow showing the separation 472, andmay extend along the full length of a side 412 of the first solar cell410. The edge 414 is located at the intersection of the side 412 of thefirst solar cell 410 and a light-facing side 416 of the first solar cell410 that couples with the plurality of electrically conductive portions420 a, 420 b, 420 c, 420 i and 420 m, for example, first portion 420 aas shown. The first solar cell 410 may include the absorber layer 410 a,the TCO layer 410 b, and the metallic substrate 410 c; a backing layer(not shown) may also be disposed between the absorber layer 410 a andthe metallic substrate 410 c. Below a back side 418 of the first solarcell 410, a first busbar (not shown) may be disposed and coupled to thefirst solar cell 410 to provide interconnection with a load (not shown).Alternatively, below the back side 418 of the first solar cell 410,another interconnect assembly (not shown) may be disposed and coupled tothe first solar cell 410 to provide interconnection with additionalsolar-cells (not shown) in the solar-cell module 404.

With reference now to FIGS. 4D and 4E, in accordance with embodiments ofthe present invention, cross-sectional, elevation views 400D and 400E,respectively, of two alternative interconnect assemblies that minimizethe separation 472 (see FIG. 4B) between the first solar cell 410 andthe second solar cell 430 to improve the solar-cell-module efficiency ofthe solar-cell module 404 are shown. In both examples shown in FIGS. 4Dand 4E, the side 412 of the first solar cell 410 essentially coincideswith the side 432 of the second solar cell 430. It should be noted thatas used herein the phrase, “essentially coincides,” with respect to theside 412 of the first solar cell 410 and the side 432 of the secondsolar cell 430 means that there is little or no separation 472 betweenthe first solar cell 410 and the second solar cell 430, and little or nooverlap of the first solar cell 410 with the second solar cell 430 sothat there is less wasted space and open area between the solar cells410 and 430, which improves the solar-collection efficiency of thesolar-cell module 404 resulting in improved solar-cell-moduleefficiency. FIG. 4D shows an edge-conforming interconnect assembly forthe physical interconnection of the two solar cells 410 and 430 in thesolar-cell module 404. FIG. 4E shows a shingled-solar-cell arrangementfor the physical interconnection of the two solar cells 410 and 430 inthe solar-cell module 404. For both the edge-conforming interconnectassembly of FIG. 4D and the shingled-solar-cell arrangement of FIG. 4E,the interconnect assembly 420 further includes the bottom carrier film460. The bottom carrier film 460 includes a second electricallyinsulating layer coupled to the trace and disposed below a bottomportion of the trace. Alternatively, The bottom carrier film 460 mayinclude a carrier film selected from a group consisting of a secondelectrically insulating layer, a structural plastic layer, and ametallic layer, and is coupled to the trace and is disposed below abottom portion of the trace. The second electrically insulating layerallows for forming the edge-protecting portion 464 at the edge 414 ofthe first solar cell 410. In the case of the edge-conforminginterconnect assembly shown in FIG. 4D, the bottom carrier film 460 andthe first portion 420 a of the interconnect assembly 420 may berelatively flexible and compliant allowing them to wrap around the edge414 and down the side 412 of the first solar cell 410, as shown. Theedge 414 is located at the intersection of the side 412 of the firstsolar cell 410 and the light-facing side 416 of the first solar cell 410that couples with the plurality of electrically conductive portions 420a, 420 b, 420 c, 420 i and 420 m, for example, first portion 420 a asshown. The first solar cell 410 may include the absorber layer 410 a, aTCO layer 410 b, and the metallic substrate 410 c; a backing layer (notshown) may also be disposed between the absorber layer 410 a and themetallic substrate 410 c. Below the back side 418 of the first solarcell 410, another interconnect assembly (not shown) or first busbar (notshown) may be disposed and coupled to the first solar cell 410 asdescribed above for FIG. 4C. If an additional solar cell (not shown) isinterconnected to the back side 418 of the first solar cell 410 as inthe shingled-solar-cell arrangement of FIG. 4E, the first solar cell 410would be pitched upward at its left-hand side and interconnected toanother interconnect assembly similar to the manner in which the secondsolar cell 430 is shown interconnected with solar cell 410 at side 412in FIG. 4E.

With further reference to FIGS. 4D and 4E, in accordance withembodiments of the present invention, the interconnect assembly 420further includes the top carrier film 450. The top carrier film 450includes a first substantially transparent, electrically insulatinglayer coupled to the trace and disposed above a top portion of thetrace. The first substantially transparent, electrically insulatinglayer allows for forming the short-circuit-preventing portion 454 at theedge 434 of the second solar cell 430 to prevent the first portion 420 afrom short circuiting the absorber layer 430 a of the second solar cell430 in the event that the first portion 420 a rides up the side 432 ofsecond solar cell 430. The edge 434 is located at the intersection ofthe side 432 of the second solar cell 430 and the back side 438 of thesecond solar cell 430 that couples with the plurality of electricallyconductive portions 420 a, 420 b, 420 c, 420 i and 420 m, for example,first portion 420 a as shown. In the case of the edge-conforminginterconnect assembly shown in FIG. 4D, the top carrier film 450 may berelatively flexible and compliant allowing it to follow the conformationof the bottom carrier film 460 and the first portion 420 a of theinterconnect assembly 420 underlying it that wrap around the edge 414and down the side 412 of the first solar cell 410, as shown. The secondsolar cell 430 may include the absorber layer 430 a, the TCO layer 430b, and the metallic substrate 430 c; a backing layer (not shown) mayalso be disposed between the absorber layer 430 a and the metallicsubstrate 430 c. Also, in the case of the edge-conforming interconnectassembly, the absorber layer 430 a, TCO layer 430 b, and metallicsubstrate 430 c of the second solar cell 430 may be relatively flexibleand compliant allowing them to follow the conformation of the underlyinginterconnect assembly 420 that wraps around the edge 414 and down theside 412 of the first solar cell 410. Above the light-facing side 436 ofthe second solar cell 430, an integrated busbar-solar-cell-currentcollector (not shown in FIG. 4C, but which is shown in FIGS. 6A and 6B),or alternatively another interconnect assembly (not shown), may bedisposed on and coupled to the second solar cell 430, as described abovefor FIG. 4C.

With reference now to FIG. 4F, in accordance with embodiments of thepresent invention, a plan view 400F of an alternative interconnectassembly for the interconnect assembly 420 of FIG. 4A is shown thatdetails the physical interconnection of two solar cells 410 and 430 inthe solar-cell module 404. The solar-cell module 404 includes the firstsolar cell 410, at least the second solar cell 430 and the interconnectassembly 420 disposed above the light-facing side 416 of the absorberlayer of the first solar cell 410. The edges 414 and 434 of the solarcells 410 and 430 may be separated by the separation 472 as shown inFIG. 4F; or alternatively, the edges 414 and 434 of the solar cells 410and 430 may essentially coincide as discussed above for FIGS. 4D and 4E.The interconnect assembly 420 includes a trace comprising a plurality ofelectrically conductive portions 420 a, 420 b, 420 c, 420 i and 420 m,previously identified herein with the resistors 420 a, 420 b, 420 c, 420i and 420 m described in FIG. 400A, where the ellipsis of 420 iindicates additional electrically conductive portions (not shown). Theplurality of electrically conductive portions 420 a, 420 b, 420 c, 420 iand 420 m is configured both to collect current from the first solarcell 410 and to interconnect electrically to the second solar cell 430.The plurality of electrically conductive portions 420 a, 420 b, 420 c,420 i and 420 m is configured such that solar-cell efficiency issubstantially undiminished in an event that any one of the plurality ofelectrically conductive portions 420 a, 420 b, 420 c, 420 i and 420 m isconductively impaired.

With further reference to FIG. 4F, in accordance with embodiments of thepresent invention, the detailed configuration of the plurality ofelectrically conductive portions 420 a, 420 b, 420 c, 420 i and 420 m isshown without electrically connecting trace portions, for example,junctions formed in the trace or linking portions of the trace. Forexample, in the case where electrically connecting trace portions of thetrace have been cut away, removed, or are otherwise absent, from thedistal ends of the plurality of electrically conductive portions 420 a,420 b, 420 c, 420 i and 420 m, as shown in FIG. 4F. The plurality ofelectrically conductive portions 420 a, 420 b, 420 c, 420 i and 420 mmay be linked together instead indirectly by the TCO layer 410 b of thefirst solar cell 410 at distal ends of the trace disposed over the firstsolar cell 410, for example, first distal end 420 p of first portion 420a and second distal end 420 q of second portion 420 b by portions of theTCO layer 410 b of the first solar cell 410 that lie in between thedistal ends 420 p and 420 q. In like fashion, the distal ends 420 w and420 q are electrically coupled through the low resistance connectionthrough the TCO layer 410 b of first solar cell 410. Similarly, theplurality of electrically conductive portions 420 a, 420 b, 420 c, 420 iand 420 m may be linked together instead indirectly by the metallicsubstrate 430 c, or intervening backing layer (not shown), of the firstsolar cell 430 at distal ends of the trace disposed under the secondsolar cell 430, for example, third distal end 420 s of second portion420 b and fourth distal end 420 t of third portion 420 c by portions ofthe metallic substrate 430 c of the second solar cell 430 that lie inbetween the distal ends 420 s and 420 t. In like fashion, the distalends 420 v and 420 s are electrically coupled through a low resistanceconnection through the metallic substrate 430 c of second solar cell430.

With further reference to FIG. 4F, in accordance with embodiments of thepresent invention, the open-circuit defect 440 is shown such that secondportion 420 b is conductively impaired. FIG. 4F illustrates the mannerin which the plurality of electrically conductive portions 420 a, 420 b,420 c, 420 i and 420 m is configured such that solar-cell efficiency issubstantially undiminished in an event that any one of the plurality ofelectrically conductive portions 420 a, 420 b, 420 c, 420 i and 420 m isconductively impaired, for example, second portion 420 b. An arrow 480indicates the nominal electron-flow through an m-th portion 420 m of theplurality of electrically conductive portions 420 a, 420 b, 420 c, 420 iand 420 m essentially unaffected by open-circuit defect 440. In theabsence of open-circuit defect 440, an electron-flow indicated by arrow480 would normally flow through any one electrically conductive portionof the plurality of electrically conductive portions 420 a, 420 b, 420c, 420 i and 420 m, in particular, second portion 420 b. However, whenthe open-circuit defect 440 is present, portions of this electron-floware lost to adjacent electrically conductive portions 420 a and 420 cshown by arrows 484 a and 484 c; arrow 482 corresponds to that portionof the normal electron-flow flowing to the right along the secondportion 420 b to the second solar cell 430, and arrow 484 b correspondsto that portion of the normal electron-flow that would bridge theopen-circuit defect 440 by flowing through the higher resistance path ofthe TCO layer 410 b bridging across the two portions of second portion420 b on either side of the open-circuit defect 440. Thus, the netelectron-flow represented by arrow 486 flowing to the right along thefirst portion 420 a is consequently larger than what would normally flowto the right along the first portion 420 a to the second solar cell 430in the absence of the open-circuit defect 440; and, the netelectron-flow represented by arrow 488 flowing to the right along thethird portion 420 c is consequently larger than what would normally flowto the right along the third portion 420 c to the second solar cell 430in the absence of the open-circuit defect 440.

Moreover, in the case of the alternative interconnect assembly depictedin FIG. 4F, as stated before for the interconnect assembly depicted inFIG. 4B, it should again be noted that open-circuit defect 440 is forillustration purposes only and that embodiments of the present inventioncompensate for other types of defects in an electrically conductiveportion, in general, such as, without limitation to: a delamination ofan electrically conductive portion from the first solar cell 410,corrosion of an electrically conductive portion, and even complete lossof an electrically conductive portion. In accordance with embodiments ofthe present invention, in the event a defect completely conductivelyimpairs an electrically conductive portion, the physical spacing betweenadjacent electrically conductive portions, identified with double-headedarrow 449, may be chosen such that solar-cell efficiency issubstantially undiminished. Nevertheless, embodiments of the presentinvention embrace, without limitation thereto, other physical spacingsbetween adjacent electrically conductive portions in the event defectsare less severe than those causing a complete loss of one of theelectrically conductive portions.

With reference now to FIG. 5A, in accordance with embodiments of thepresent invention, a plan view 500A of the combined applicable carrierfilm, interconnect assembly 504 is shown. FIG. 5A shows the physicalarrangement of a trace 520 with respect to a top carrier film 550 and abottom carrier film 560 in the combined applicable carrier film,interconnect assembly 504. The combined applicable carrier film,interconnect assembly 504 includes the top carrier film 550 and thetrace 520 including a plurality of electrically conductive portions 520a, 520 b, 520 c, 520 d, 520 e, 520 f, 520 g, 520 m and 520 i, the lattercorresponding to the ellipsis indicating additional electricallyconductive portions (not shown). The plurality of electricallyconductive portions 520 a through 520 m is configured both to collectcurrent from a first solar cell 510 (shown in FIG. 5C) and tointerconnect electrically to a second solar cell (not shown). As shownin FIG. 5A, the plurality of electrically conductive portions 520 athrough 520 m run over the top of the first solar cell 510 on the leftand over an edge 514 of the first solar cell 510 to the right under anedge 534 of, and underneath, the second solar cell (not shown). The topcarrier film 550 includes a first substantially transparent,electrically insulating layer 550A (shown in FIG. 5B). The plurality ofelectrically conductive portions 520 a through 520 m is configured suchthat solar-cell efficiency is substantially undiminished in an eventthat any one of the plurality of electrically conductive portions 520 athrough 520 m is conductively impaired. It should be noted that as usedherein the phrase, “substantially transparent,” with respect to asubstantially transparent, electrically insulating layer means thatlight passes through the substantially transparent, electricallyinsulating layer with negligible absorption. The first substantiallytransparent, electrically insulating layer 550 a is coupled to the trace520 and disposed above a top portion of the trace 520 (shown in FIG. 5B)as indicated by the dashed portions of the trace 520 on the left of FIG.5A.

With reference now to FIGS.5B and 5C, in accordance with embodiments ofthe present invention, a cross-sectional, elevation view of the combinedapplicable carrier film, interconnect assembly 504 of FIG. 5A is shown.As shown in FIGS. 5B and 5C, the cross-section of the view is takenalong a cut parallel to the edge 514 of the first solar cell 510. Thecross-sectional, elevation view of FIG. 5B shows the physicalarrangement of the trace 520 with respect to the top carrier film 550 inthe combined applicable carrier film, interconnect assembly 504 prior todisposition on the first solar cell 510. On the other hand, thecross-sectional, elevation view of FIG. 5C shows the physicalarrangement of the trace 520 with respect to the top carrier film 550and the first solar cell 510 of the combined applicable carrier film,interconnect assembly 504 after it couples with the first solar cell510. The top carrier film 550 and the trace 520 are configured forapplying to a light-facing side of the first solar cell 510 both tocollect current from the first solar cell 510 and to interconnectelectrically to the second solar cell (not shown). The first solar cell510 may include an absorber layer 510 a, a TCO layer 510 b, and ametallic substrate 510 c; the backing layer (not shown) may also bedisposed between the absorber layer 510 a and the metallic substrate 510c. The first substantially transparent, electrically insulating layer550 a holds the trace 520 down in contact with the first solar cell 510and allows for forming a short-circuit-preventing portion at an edge ofthe second solar cell (not shown). The top carrier film 550 furtherincludes a first substantially transparent, adhesive medium 550 bcoupling the trace 520 to the substantially transparent, electricallyinsulating layer 550 a. As shown in FIG. 5B, prior to disposition on thefirst solar cell 510, the top carrier film 550 lies relatively flatacross the top portion of the trace 520, for example, as for theconformational state of the top carrier film 550 immediately afterroll-to-roll fabrication of the combined applicable carrier film,interconnect assembly 504. In contrast, after disposition on the firstsolar cell 510, the top carrier film 550 conforms to the top portion ofthe trace 520, as shown in FIG. 5B. The first substantially transparent,adhesive medium 550 b allows for coupling the trace 520 to the firstsolar cell 510 without requiring solder. The first substantiallytransparent, electrically insulating layer 550 a may include astructural plastic material, such as polyethylene terephthalate (PET).In accordance with embodiments of the present invention, a firstsubstantially transparent, adhesive medium such as first substantiallytransparent, adhesive medium 550 b may be included, without limitationthereto, in a top carrier film of: the combined applicable carrier film,interconnect assembly 504, the interconnect assembly 320, the integratedbusbar-solar-cell-current collector 690 (see FIG. 6B), the combinedsolar-cell, interconnect assembly 494, or the interconnect assembly 420of the solar-cell module 404.

With further reference to FIGS. 5A, 5B and 5C, in accordance withembodiments of the present invention, the combined applicable carrierfilm, interconnect assembly 504 further includes the bottom carrier film560. The bottom carrier film 560 includes a second electricallyinsulating layer, like 550 a, coupled to the trace 520 and disposedbelow a bottom portion of the trace 520, as indicated by the solid-lineportions of the trace 520 on the right of FIG. 5A. Alternatively, thebottom carrier film 560 may include a carrier film selected from a groupconsisting of a second electrically insulating layer, a structuralplastic layer, and a metallic layer, and is coupled to the trace 520 andis disposed below a bottom portion of the trace 520. The secondelectrically insulating layer, like 550 a, holds the trace 520 down incontact with a back side of the second solar cell (not shown) and allowsfor forming an edge-protecting portion at the edge 514 of the firstsolar cell 510. The bottom carrier film 560 further includes a secondadhesive medium, like 550 b, coupling the trace to the secondelectrically insulating layer, like 550 a. The second adhesive medium,like 550 b, allows for coupling the trace 520 to the back side of thesecond solar cell (not shown) without requiring solder. The secondelectrically insulating layer, like 550 a, includes a structural plasticmaterial, such as PET. In accordance with embodiments of the presentinvention, a second adhesive medium, like 550 b, may be included,without limitation thereto, in a bottom carrier film of: the combinedapplicable carrier film, interconnect assembly 504, the interconnectassembly 320, the combined solar-cell, interconnect assembly 494, or theinterconnect assembly 420 of the solar-cell module 404.

With further reference to FIG. 5A, in accordance with embodiments of thepresent invention, the trace 520 may be disposed in a serpentine patternthat allows for collecting current from the first solar cell 510 (shownin FIG. 5C) and electrically interconnecting to the second solar cell(not shown). It should be noted that neither the first solar cell 510nor the second solar cell (not shown) are shown in FIG. 5A so as not toobscure the structure of the combined applicable carrier film,interconnect assembly 504. As shown in FIG. 5A, the combined applicablecarrier film, interconnect assembly 504 includes the trace 520 includingthe plurality of electrically conductive portions 520 a through 520 mthat may run in a serpentine pattern back and forth between the firstsolar cell 510 and the second solar cell (not shown). The serpentinepattern is such that adjacent electrically conductive portions of theplurality of electrically conductive portions 520 a through 520 m areconfigured in pairs of adjacent electrically conductive portions: 520 aand 520 b, 520 c and 520 d, 520 e and 520 f, etc. The pairs of adjacentelectrically conductive portions may be configured in a regularrepeating pattern of equally spaced adjacent electrically conductiveportions. The trace 520 including the plurality of electricallyconductive portions 520 a through 520 m is disposed between the topcarrier film 550 disposed above a top portion of the trace 520 and thebottom carrier film 560 disposed below a bottom portion of the trace520. The first substantially transparent, electrically insulating layer550 a of top carrier film 550 and the second electrically insulatinglayer, or alternatively, structural plastic layer or metallic layer, ofbottom carrier film 560 are coupled to the trace 520 with a firstsubstantially transparent, adhesive medium 550 b and second adhesivemedium which also serve to couple the trace 520 to the first solar cell510, which may be located on the left, and the second solar cell, whichmay be located on the right. In the space between the two solar cells,between the edge 514 of the first solar cell and the edge 534 of thesecond solar cell, the trace is sandwiched between the two carrier films550 and 560; the overlapping region of the two carrier films 550 and 560extends somewhat beyond the respective edges 514 and 534 of the firstand second solar cells so as to form, respectively, an edge-protectingportion at the edge 514 of the first solar cell, and ashort-circuit-preventing portion at the edge 534 of the second solarcell, from the trace 520 that crosses the edges 514 and 534.

With further reference to FIGS. 5B and 5C, in accordance withembodiments of the present invention, the trace 520 may further includean electrically conductive line including a conductive core 520A with atleast one overlying layer 520B. In one embodiment of the presentinvention, the electrically conductive line may include the conductivecore 520A including a material having greater conductivity than nickel,for example, copper, with an overlying nickel layer 520B. In anotherembodiment of the present invention, electrically conductive line mayinclude the conductive core 520A including nickel without the overlyinglayer 520B. The electrically conductive line may also be selected from agroup consisting of a copper conductive core clad with a silvercladding, a copper conductive core clad with a nickel coating furtherclad with a silver cladding and an aluminum conductive core clad with asilver cladding.

With further reference to FIGS. 5B and 5C, in accordance withembodiments of the present invention, the trace 520 for collectingcurrent from a solar cell, for example the first solar cell 510, mayinclude an electrically conductive line including the conductive core520A, and the overlying layer 520B that limits current flow to aproximate shunt defect (not shown) in the solar cell. The proximateshunt defect may be proximately located in the vicinity of an electricalcontact between the overlying layer 520B of the electrically conductiveline and the TCO layer 510 b of the solar cell, for example, first solarcell 510. The overlying layer 520B of the electrically conductive lineof the trace 520 may further include an overlying layer 520B composed ofnickel. The conductive core 520A of the electrically conductive line ofthe trace 520 may further include nickel. The conductive core 520A mayalso include a material selected from a group consisting of copper,silver, aluminum, and elemental constituents and alloys having highelectrical conductivity, which may be greater than the electricalconductivity of nickel. The TCO layer 510 b of the solar cell, forexample first solar cell 510, may include a conductive oxide selectedfrom a group consisting of zinc oxide, aluminum zinc oxide and indiumtin oxide. In addition, the absorber layer 510 a, for example, absorberlayer 112 of FIG. 1A, of the solar cell, for example, first solar cell510, may include copper indium gallium diselenide (CIGS). Alternatively,in embodiments of the present invention, it should be noted thatsemiconductors, such as silicon, cadmium telluride, and chalcopyritesemiconductors, as well as other semiconductors, may be used as theabsorber layer 510 a. Moreover, an n-type layer, for example, n-typeportion 112 b of absorber layer 112 of FIG. 1A, of the solar cell, forexample, first solar cell 510, may be disposed on and electricallycoupled to a p-type absorber layer, for example, absorber layer 112 ofFIG. 1A, of the solar cell, for example, first solar cell 510, and then-type layer, for example, n-type portion 112 b of absorber layer 112 ofFIG. 1A, may be selected from a group consisting of a metal oxide, ametal sulfide and a metal selenide.

Although the trace 520 is shown as having a circular cross-sectionhaving a point-like contact with a solar cell, for example, with the TCOlayer 510 b, or, without limitation thereto, to a top surface, of thefirst solar cell 510, embodiments of the present inventions include,without limitation thereto, other cross-sectional profiles of the trace520, such as a profile including a flattened top portion and a flattenedbottom portion, so as to increase the contact area between the trace 520and a solar cell with which it makes contact. For example, a flattenedbottom portion of trace 520 increases the contact area with thelight-facing side of the first solar cell 510; on the other hand, aflattened top portion of trace 520 increases the contact area with aback side of an adjacent solar cell to which the plurality ofelectrically conductive portions 520 a through 520 m of the trace 520interconnects. In accordance with embodiments of the present invention,a trace, such as trace 520, may be included, without limitation thereto,in: the combined applicable carrier film, interconnect assembly 504, theinterconnect assembly 320, the integrated busbar-solar-cell-currentcollector 690 (see FIG. 6B), the combined solar-cell, interconnectassembly 494, or the interconnect assembly 420 of the solar-cell module404.

With reference now to FIG. 6A, in accordance with embodiments of thepresent invention, a plan view 600A of an integratedbusbar-solar-cell-current collector 690 is shown. FIG. 6A shows thephysical interconnection of a terminating solar cell 660 with aterminating busbar 680 of the integrated busbar-solar-cell-currentcollector 690. The integrated busbar-solar-cell-current collector 690includes the terminating busbar 680 and an integrated solar-cell,current collector 670. The integrated solar-cell, current collector 670includes a plurality of integrated pairs 670 a&b, 670 c&d, 670 e&f, 670g&h, and 670 l&m and 670 i, the ellipsis indicating additionalintegrated pairs (not shown), of electrically conductive, electricallyparallel trace portions 670 a-m. Throughout the following, therespective integrated pairs: 670 a and 670 b, 670 c and 670 d, 670 e and670 f, 670 g and 670 h, and 670 l and 670 m, are referred torespectively as: 670 a&b, 670 c&d, 670 e&f, 670 g&h, and 670 l&m; andthe electrically conductive, electrically parallel trace portions: 670a, 670 b, 670 c, 670 d, 670 e, 670 f, 670 g, 670 h, 670 l and 670 m, arereferred to as 670 a-m. The plurality of integrated pairs 670 a&b, 670c&c, 670 e&f, 670 g&h, 670 i and 670 l&m of electrically conductive,electrically parallel trace portions 670 a-m is configured both tocollect current from the terminating solar cell 660 and to interconnectelectrically to the terminating busbar 680. The plurality of integratedpairs 670 a&b, 670 c&c, 670 e&f, 670 g&h, 670 i and 670 l&m ofelectrically conductive, electrically parallel trace portions 670 a-m isconfigured such that solar-cell efficiency is substantially undiminishedin an event that any one electrically conductive, electrically paralleltrace portion, for example, 670 h, of the plurality of integrated pairs670 a&b, 670 c&c, 670 e&f, 670 g&h, 670 i and 670 l&m of electricallyconductive, electrically parallel trace portions 670 a-m is conductivelyimpaired.

With further reference to FIGS. 6A and 6B, in accordance withembodiments of the present invention, the plurality of integrated pairs670 a&b, 670 c&c, 670 e&f, 670 g&h, 670 i and 670 l&m of electricallyconductive, electrically parallel trace portions 670 a-m furtherincludes a first electrically conductive, electrically parallel traceportion 670 a of a first integrated pair 670 a&b of the electricallyconductive, electrically parallel trace portions 670 a-m configured bothto collect current from the terminating solar cell 660 and tointerconnect electrically to the terminating busbar 680, and a secondelectrically conductive, electrically parallel trace portion 670 b ofthe first integrated pair 670 a&b of the electrically conductive,electrically parallel trace portions 670 a-m configured both to collectcurrent from the terminating solar cell 660 and to interconnectelectrically to the terminating busbar 680. The first electricallyconductive, electrically parallel trace portion 670 a includes a firstend 670 p distal from the terminating busbar 680 located parallel to aside 662 of the terminating solar cell 660. The second electricallyconductive, electrically parallel trace portion 670 b includes a secondend 670 q distal from the terminating busbar 680. The secondelectrically conductive, electrically parallel trace portion 670 b isdisposed proximately to the first electrically conductive, electricallyparallel trace portion 670 a and electrically connected to the firstelectrically conductive, electrically parallel trace portion 670 a suchthat the first distal end 670 p is electrically connected to the seconddistal end 670 q, for example, at first junction 670 r, or by a linkingportion, such that the second electrically conductive, electricallyparallel trace portion 670 b is configured electrically in parallel tothe first electrically conductive, electrically parallel trace portion670 a when configured to interconnect to the terminating busbar 680. Inaddition, in accordance with embodiments of the present invention, theterminating busbar 680 may be disposed above and connected electricallyto extended portions, for example, 670 x and 670 y, of the plurality ofintegrated pairs 670 a&b, 670 c&c, 670 e&f, 670 g&h, 670 i and 670 l&mof electrically conductive, electrically parallel trace portions 670 a-mconfigured such that the terminating busbar 680 is configured to reduceshadowing of the terminating solar cell 660.

With further reference to FIG. 6A, in accordance with embodiments of thepresent invention, an open-circuit defect 640 is shown such that eighthelectrically conductive, electrically parallel trace portion 670 h isconductively impaired. FIG. 6A illustrates the manner in which theplurality of integrated pairs 670 a&b, 670 c&c, 670 e&f, 670 g&h and 670l&m of electrically conductive, electrically parallel trace portions 670a-m is configured such that solar-cell efficiency is substantiallyundiminished in an event that any one electrically conductive,electrically parallel trace portion, for example, eighth electricallyconductive, electrically parallel trace portion 670 h, of the pluralityof integrated pairs 670 a&b, 670 c&c, 670 e&f, 670 g&h and 670 l&m ofelectrically conductive, electrically parallel trace portions 670 a-m isconductively impaired. The arrow 648 indicates the nominal electron-flowthrough a sixth electrically conductive, electrically parallel traceportion 670 f of the plurality of integrated pairs 670 a&b, 670 c&c, 670e&f, 670 g&h and 670 l&m of electrically conductive, electricallyparallel trace portions 670 a-m essentially unaffected by open-circuitdefect 640. In the absence of open-circuit defect 640, an electron-flowindicated by arrow 648 would normally flow through any one electricallyconductive, electrically parallel trace portion of the plurality ofintegrated pairs 670 a&b, 670 c&c, 670 e&f, 670 g&h and 670 l&m ofelectrically conductive, electrically parallel trace portions 670 a-m,in particular, eighth electrically conductive, electrically paralleltrace portion 670 h. However, when the open-circuit defect 640 ispresent, this electron-flow divides into two portions shown by arrows642 and 644: arrow 642 corresponding to that portion of the normalelectron-flow flowing to the right along the eighth electricallyconductive, electrically parallel trace portion 670 h to the terminatingbusbar 680, and arrow 644 corresponding to that portion of the normalelectron-flow flowing to the left along the eighth electricallyconductive, electrically parallel trace portion 670 h to the seventhelectrically conductive, electrically parallel trace portion 670 g andthen to the right along the seventh electrically conductive,electrically parallel trace portion 670 g to the terminating busbar 680.Thus, the net electron-flow represented by arrow 646 flowing to theright along the seventh electrically conductive, electrically paralleltrace portion 670 g is consequently larger than what would normally flowto the right along the seventh electrically conductive, electricallyparallel trace portion 670 g to the terminating busbar 680 in theabsence of the open-circuit defect 640. It should be noted thatopen-circuit defect 640 is for illustration purposes only and thatembodiments of the present invention compensate for other types ofdefects in an electrically conductive, electrically parallel traceportion, in general, such as, without limitation to: a delamination ofan electrically conductive, electrically parallel trace portion from theterminating solar cell 660, corrosion of an electrically conductive,electrically parallel trace portion, and even complete loss of anelectrically conductive, electrically parallel trace portion. Inaccordance with embodiments of the present invention, in the event adefect completely conductively impairs an electrically conductive,electrically parallel trace portion, the physical spacing betweenadjacent electrically conductive, electrically parallel trace portions,identified with double-headed arrow 649, may be chosen such thatsolar-cell efficiency is substantially undiminished. Nevertheless,embodiments of the present invention embrace, without limitationthereto, other physical spacings between adjacent electricallyconductive, electrically parallel trace portions in the event defectsare less severe than those causing a complete loss of one of theelectrically conductive, electrically parallel trace portions.

With reference now to FIG. 6B and further reference to FIG. 6A, inaccordance with embodiments of the present invention, a cross-sectional,elevation view 600B of the integrated busbar-solar-cell-currentcollector 690 of FIG. 6A is shown. FIG. 6B shows the physicalinterconnection of the terminating solar cell 660 with the terminatingbusbar 680 in the integrated busbar-solar-cell-current collector 690. Inaccordance with embodiments of the present invention, theinterconnection approach employing a carrier film is also conducive tocoupling the integrated busbar-solar-cell-current collector 690 directlyto the terminating busbar 680 without requiring solder. Thus, theintegrated busbar-solar-cell-current collector 690 further includes atop carrier film 650. The top carrier film 650 includes a firstsubstantially transparent, electrically insulating layer (not shown, butlike 550 a of FIG. 5B) coupled to the plurality of integrated pairs 670a&b, 670 c&c, 670 e&f, 670 g&h, 670 i and 670 l&m of electricallyconductive, electrically parallel trace portions 670 a-m, for example,electrically conductive, electrically parallel trace portion 670 a, anddisposed above a top portion of the plurality of integrated pairs 670a&b, 670 c&c, 670 e&f, 670 g&h, 670 i and 670 l&m of electricallyconductive, electrically parallel trace portions 670 a-m.

With further reference to FIGS. 6A and 6B, in accordance withembodiments of the present invention, the top carrier film 650 furtherincludes a first adhesive medium (not shown, but like 550 b of FIGS. 5Band 5C) coupling the plurality of integrated pairs 670 a&b, 670 c&c, 670e&f, 670 g&h, 670 i and 670 l&m of electrically conductive, electricallyparallel trace portions 670 a-m to the electrically insulating layer(like 550 a of FIG. 5B). The first adhesive medium (like 550 b of FIGS.5B and 5C) allows for coupling the plurality of integrated pairs 670a&b, 670 c&c, 670 e&f, 670 g&h, 670 i and 670 l&m of electricallyconductive, electrically parallel trace portions 670 a-m to theterminating solar cell 660 without requiring solder. The terminatingsolar cell 660 may include an absorber layer 660 a, a TCO layer 660 b,and a metallic substrate 660 c; a backing layer (not shown) may also bedisposed between the absorber layer 660 a and the metallic substrate 660c. The plurality of integrated pairs of electrically conductive,electrically parallel trace portions 670 a-m may be connectedelectrically in series to form a single continuous electricallyconductive line (not shown). The single continuous electricallyconductive line may be disposed in a serpentine pattern (not shown, butlike the pattern of trace 520 in FIG. 5A) such that the integratedbusbar-solar-cell-current collector 690 is configured to collect currentfrom the terminating solar cell 660 and to interconnect electrically tothe terminating busbar 680. The plurality of integrated pairs 670 a&b,670 c&c, 670 e&f, 670 g&h, 670 i and 670 l&m of electrically conductive,electrically parallel trace portions 670 a-m may further include aplurality of electrically conductive lines (not shown, but like trace520 of FIGS. 5B and 5C), any electrically conductive line of theplurality of electrically conductive lines selected from a groupconsisting of a copper conductive core clad with a silver cladding, acopper conductive core clad with a nickel coating further clad with asilver cladding and an aluminum conductive core clad with a silvercladding.

With further reference to FIGS. 6A and 6B, in accordance withembodiments of the present invention, integratedbusbar-solar-cell-current collector 690 may include a supplementaryisolation strip (not shown) at an edge 664 of the terminating solar cell660 and running along the length of the side 662 to provide additionalprotection at the edge 664 and side 662 of the terminating solar cell660 from the extended portions, for example, 670 x and 670 y, of theplurality of integrated pairs 670 a&b, 670 c&c, 670 e&f, 670 g&h, 670 iand 670 l&m of electrically conductive, electrically parallel traceportions 670 a-m. In another embodiment of the present invention, theextended portions, for example, 670 x and 670 y, may be configured (notshown) to provide stress relief and to allow folding the terminatingbusbar 680 along edge 664 under a back side 668 and at the side 662 ofterminating solar cell 660, so that there is less wasted space and openarea between the terminating solar cell 660 of one module and theinitial solar cell (not shown) of an adjacent module. Moreover,integrated busbar-solar-cell-current collector 690 may include asupplementary carrier-film strip (not shown) at the edge 664 of theterminating solar cell 660 and running along the length of the side 662disposed above and coupled to top carrier film 650 and the terminatingbusbar 680 to affix the terminating busbar 680 to the extended portions,for example, 670 x and 670 y. Alternatively, the integratedbusbar-solar-cell-current collector 690 may include the top carrier film650 extending over the top of the terminating busbar 680 and extendedportions, for example, 670 x and 670 y, to affix the terminating busbar680 to these extended portions. Thus, these latter two embodiments ofthe present invention provide a laminate including the terminatingbusbar 680 disposed between top carrier film 650, or alternatively thesupplementary carrier-film strip, and the supplementary isolation strip(not shown) along the edge 664 and side 662 of the terminating solarcell 660. Moreover, the top carrier film 650, or the supplementarycarrier-film strip, is conducive to connecting the terminating busbar680 without requiring solder to the plurality, itself, or to theextended portions, for example, 670 x and 670 y, of the plurality ofintegrated pairs 670 a&b, 670 c&c, 670 e&f, 670 g&h, 670 i and 670 l&mof electrically conductive, electrically parallel trace portions 670 a-m

With reference now to FIG. 7A, in accordance with embodiments of thepresent invention, a combined cross-sectional elevation and perspectiveview of a roll-to-roll, interconnect-assembly fabricator 700A is shown.FIG. 7A shows the roll-to-roll, interconnect-assembly fabricator 700Aoperationally configured to fabricate an interconnect assembly 720. Atop carrier film 716 including an electrically insulating layer, forexample a first substantially transparent, electrically insulatinglayer, is provided to roll-to-roll, interconnect-assembly fabricator700A in roll form from a first roll of material 714. The roll-to-roll,interconnect-assembly fabricator 700A includes an first unwinding spool710 upon which the first roll of material 714 of the top carrier film716 including the electrically insulating layer is mounted. As shown, aportion of the first roll of material 714 is unrolled. The unrolledportion of the top carrier film 716 including the electricallyinsulating layer passes to the right and is taken up on a take-up spool718 upon which it is rewound as a third roll 722 of interconnectassembly 720, after conductive-trace material 750 is provided from adispenser 754 and is laid down onto the unrolled portion of the topcarrier film 716 including the electrically insulating layer. Thedispenser 754 of conductive-trace material 750 may be a spool of wire,or some other container providing conductive-trace material. Theconductive-trace material 750 may be laid down onto the unrolled portionof the top carrier film 716 including the electrically insulating layerin an oscillatory motion, but without limitation to a strictlyoscillatory motion, indicated by double-headed arrow 758, to create afirst plurality of electrically conductive portions configured both tocollect current from a first solar cell and to interconnect electricallyto a second solar cell such that solar-cell efficiency is substantiallyundiminished in an event that any one of the first plurality ofelectrically conductive portions is conductively impaired. As shown inFIG. 7A, a portion of the electrically conductive portions overhang oneside of the top carrier film 716 to allow the electrically conductiveportions of the trace to interconnect electrically to the second solarcell on the exposed top side of the trace, while the exposed bottom sideof the trace, here shown as facing upward on the top carrier film 716,allows the electrically conductive portions of the trace in contact withthe top carrier film 716 to interconnect electrically to the first solarcell. Moreover, the conductive-trace material 750 may be disposed in aserpentine pattern to create the plurality of electrically conductiveportions configured both to collect current from the first solar celland to interconnect electrically to the second solar cell. The arrowsadjacent to the first unwinding spool 710, and the take-up spool 718indicate that these are rotating components of the roll-to-roll,interconnect-assembly fabricator 700A; the first unwinding spool 710,and the take-up spool 718 are shown rotating in clockwise direction, asindicated by the arrow-heads on the respective arrows adjacent to thesecomponents, to transport the unrolled portion of the first roll ofmaterial 714 from the first unwinding spool 710 on the left to thetake-up spool 718 on the right.

With reference now to FIG. 7B, in accordance with embodiments of thepresent invention, a combined cross-sectional elevation and perspectiveview of a roll-to-roll, laminated-interconnect-assembly fabricator 700Bis shown. FIG. 7A shows the roll-to-roll,laminated-interconnect-assembly fabricator 700B operationally configuredto fabricate a laminated-interconnect assembly 740. The roll-to-roll,laminated-interconnect-assembly fabricator 700B first fabricates theinterconnect assembly 720 shown on the left-hand side of FIG. 7B fromthe first roll of material 714 of the top carrier film 716 including theelectrically insulating layer and from conductive-trace material 750provided from dispenser 754. Then, the roll-to-roll,laminated-interconnect-assembly fabricator 700B continues fabrication ofthe laminated-interconnect assembly 740 by applying a bottom carrierfilm 736 from a second roll 734. The bottom carrier film 736 includes acarrier film selected from a group consisting of a second electricallyinsulating layer, a structural plastic layer, and a metallic layer, andis coupled to the conductive-trace material 750 and is disposed below abottom portion of the conductive-trace material 750. If a metallic layeris used for the bottom carrier film 736, a supplementary isolation strip(not shown) of a third electrically insulating layer is added to thelaminated-interconnect assembly 740 configured to allow interposition ofthe third electrically insulating layer between the bottom carrier film736 and a top surface of the first solar cell to provide additionalprotection at an edge of the first solar cell and to prevent shortingout the solar cell in the event that the bottom carrier film 736including the metallic layer should ride down the side of the firstsolar cell. The laminated-interconnect assembly 740 passes to theright-hand side of FIG. 7B and is taken up on the take-up spool 718 uponwhich it is wound as a fourth roll 742 of laminated-interconnectassembly 740. The arrows adjacent to the first unwinding spool 710, asecond unwinding spool 730 and the take-up spool 718 indicate that theseare rotating components of the roll-to-roll,laminated-interconnect-assembly fabricator 700B; the first unwindingspool 710, and the take-up spool 718 are shown rotating in clockwisedirection, as indicated by the arrow-heads on the respective arrowsadjacent to these components, to transport the unrolled portion of thefirst roll of material 714 from the first unwinding spool 710 on theleft to the take-up spool 718 on the right. The second unwinding spool730, and the dispenser 754 are shown rotating in a counterclockwisedirection and a clockwise direction, respectively, as indicated by thearrow-heads on the respective arrows adjacent to these components, asthey release the bottom carrier layer 736 and the conductive-tracematerial 750, respectively, in fabrication of the laminated-interconnectassembly 740. The double-headed arrow 758 indicates the motion impartedto the conductive trace material by the roll-to-roll,laminated-interconnect-assembly fabricator 700B creates a firstplurality of electrically conductive portions configured both to collectcurrent from a first solar cell and to interconnect electrically to asecond solar cell such that solar-cell efficiency is substantiallyundiminished in an event that any one of the first plurality ofelectrically conductive portions is conductively impaired.

Description of Embodiments of the Present Invention for a Method forRoll-to-Roll Fabrication of an Interconnect Assembly

With reference now to FIG. 8, a flow chart illustrates an embodiment ofthe present invention for a method for roll-to-roll fabrication of aninterconnect assembly. At 810, a first carrier film including a firstsubstantially transparent, electrically insulating layer is provided inroll form. At 820, a trace is provided from a dispenser ofconductive-trace material. The dispenser may be a spool of wire or othercontainer of conductive-trace material. At 830, a portion of the firstcarrier film including the first substantially transparent, electricallyinsulating layer is unrolled. At 840, the trace from the dispenser ofconductive-trace material is laid down onto the portion of the firstcarrier film including the first substantially transparent, electricallyinsulating layer. At 850, the trace is configured as a first pluralityof electrically conductive portions such that solar-cell efficiency issubstantially undiminished in an event that any one of the firstplurality of electrically conductive portions is conductively impaired.At 860, the portion of the first said first carrier film including thesubstantially transparent, electrically insulating layer is coupled to atop portion of the trace to provide an interconnect assembly.

In an embodiment of the present invention, configuring the trace alsoincludes: configuring the trace as a second plurality of paired traceportions; configuring a first portion of a paired portion of the secondplurality of paired trace portions to allow both collecting current froma first solar cell and electrically interconnecting the first solar cellwith a second solar cell; disposing proximately to the first portion, asecond portion of the paired portion; and configuring the second portionto allow both collecting current from the first solar cell andelectrically interconnecting the first solar cell with the second solarcell. Alternatively, configuring the trace may include disposing thetrace in a serpentine pattern that allows for collecting current fromthe first solar cell and electrically interconnecting to the secondsolar cell. In an embodiment of the present invention, the method mayalso include: providing a second carrier film including a secondelectrically insulating layer; coupling the second carrier filmincluding the second electrically insulating layer to a bottom portionof the trace; and configuring the second electrically insulating layerto allow forming an edge-protecting portion at an edge of the firstsolar cell. Moreover, the method may include configuring the firstsubstantially transparent, electrically insulating layer to allowforming a short-circuit-preventing portion at an edge of the secondsolar cell.

Description of Embodiments of the Present Invention for a Method ofInterconnecting Two Solar Cells

With reference now to FIG. 9, a flow chart illustrates an embodiment ofthe present invention for a method of interconnecting two solar cells.At 910, a first solar cell and at least a second solar cell areprovided. At 920, a combined applicable carrier film, interconnectassembly including a trace including a plurality of electricallyconductive portions is provided. At 930, the plurality of electricallyconductive portions of the trace is configured both to collect currentfrom the first solar cell and to interconnect electrically with thesecond solar cell such that solar-cell efficiency is substantiallyundiminished in an event that any one of the plurality of electricallyconductive portions is conductively impaired. At 940, the combinedapplicable carrier film, interconnect assembly is applied and coupled toa light-facing side of the first solar cell. At 950, the combinedapplicable carrier film, interconnect assembly is applied and coupled toa back side of the second solar cell.

In an embodiment of the present invention, the method also includesapplying and coupling the combined applicable carrier film, interconnectassembly to the light-facing side of the first solar cell withoutrequiring solder. In addition, the method may include applying andcoupling the combined applicable carrier film, interconnect assembly tothe back side of the second solar cell without requiring solder.Moreover, the method includes applying and coupling the combinedapplicable carrier film, interconnect assembly to the light-facing sideof the first solar cell such that a second electrically insulating layerof the applicable carrier film, interconnect assembly forms anedge-protecting portion at an edge of the first solar cell. The methodalso includes applying and coupling the combined applicable carrierfilm, interconnect assembly to the back side of the second solar cellsuch that a first substantially transparent, electrically insulatinglayer of the applicable carrier film, interconnect assembly forms ashort-circuit-preventing portion at an edge of the second solar cell.The method may also include configuring the trace in a serpentinepattern that allows for collecting current from the first solar cell andelectrically interconnecting to the second solar cell.

Physical Description of Embodiments of the Present Invention for a Trace

In accordance with other embodiments of the present invention, the tracedoes not need to be used in conjunction with the afore-mentionedserpentine interconnect assembly approach, but could be used for othercurrent collection and/or interconnection approaches used in solar celltechnology. A trace including a conductive core with an overlying layerof nickel provides the unexpected result that when placed in contactwith the TCO layer of a solar cell it suppresses current in the vicinityof short-circuit defects in the solar cell that might occur in thevicinity of the contact of the nickel layer of the trace with the TCOlayer. The nickel increases local contact resistance which improves theability of the solar cell to survive in the event of the formation of adefect, such as a shunt or a near shunt, located in the adjacentvicinity of the contact of the nickel layer of the trace with the TCOlayer. If there is such a defect in the vicinity of the contact of thenickel layer of the trace with the TCO layer, the nickel reduces thetendency of the solar cell to pass increased current through the site ofthe defect, such as a shunt or a near shunt. Thus, the nickel acts as alocalized resistor preventing run-away currents and high currentdensities in the small localized area associated with the site of thedefect, such as a shunt or a near shunt. The current-limiting ability ofnickel is in contrast, for example, to a low resistivity material suchas silver, where the current density becomes so high at the location ofthe defect due to the high conductivity of silver that nearly almost allthe current of the cell would be passed at the location of the defectcausing a hot spot that would result in the melting of the silver withthe formation of a hole in the solar cell filling with the silvermigrating to the site of the defect to form a super-shunt. In contrast,nickel does not readily migrate nor melt in the presence of elevatedlocalized temperatures associated with the site of increased currentsattending formation of the defect, such as a shunt or a near shunt.Moreover, in contrast to silver, copper and tin, which tend toelectromigrate, migrate or diffuse at elevated temperatures, nickeltends to stay put so that if the site of a shunt occurs in the vicinityof a nickel coated or nickel trace, the nickel has less tendency to moveto the location of the shunt thereby further exacerbating the drop ofresistance at the shunt site. In addition, experimental results of thepresent invention indicate that a nickel trace, or a trace including anickel layer, may actually increase its resistance due the possibleformation of a nickel oxide such that the nickel trace, or the traceincluding the nickel layer, acts like a localized fuse limiting thecurrent flow in the vicinity of the shunt site. In some cases, theefficiency of the solar cell has actually been observed to increaseafter formation of the shunt defect when the nickel trace, or the traceincluding the nickel layer, is used in contact with the TCO layer.

With further reference to FIGS. 5B and 5C, in accordance with otherembodiments of the present invention, the trace 520 for collectingcurrent from a solar cell, for example, first solar cell 510, includesan electrically conductive line including the conductive core 520A, andthe overlying layer 520B that limits current flow to a proximate shuntdefect (not shown) in the solar cell, for example, first solar cell 510.The proximate shunt defect may be proximately located in the vicinity ofan electrical contact between the overlying layer 520B of theelectrically conductive line and the TCO layer 510 b of the solar cell,for example, first solar cell 510. The overlying layer 520B of theelectrically conductive line of the trace 520 may further include anoverlying layer 520B composed of nickel. The conductive core 520A of theelectrically conductive line of the trace 520 may further includenickel. The conductive core 520A may also include a material selectedfrom a group consisting of copper, silver, aluminum, and elementalconstituents and alloys having high electrical conductivity, which maybe greater than the electrical conductivity of nickel. The TCO layer 510b of the solar cell, for example, first solar cell 510, may include aconductive oxide selected from a group consisting of zinc oxide,aluminum zinc oxide and indium tin oxide. In addition, the absorberlayer 510 a, for example, absorber layer 112 of FIG. 1A, of the solarcell, for example, first solar cell 510, may include copper indiumgallium diselenide (CIGS). Alternatively, in embodiments of the presentinvention, it should be noted that semiconductors, such as silicon,cadmium telluride, and chalcopyrite semiconductors, as well as othersemiconductors, may be used as the absorber layer 510 a. Moreover, ann-type layer, for example, n-type portion 112 b of absorber layer 112 ofFIG. 1A, of the solar cell, for example, first solar cell 510, may bedisposed on and electrically coupled to a p-type absorber layer, forexample, absorber layer 112 of FIG. 1A, of the solar cell, for example,first solar cell 510, and the n-type layer, for example, n-type portion112 b of absorber layer 112 of FIG. 1A, may be selected from a groupconsisting of a metal oxide, a metal sulfide and a metal selenide.

The foregoing descriptions of specific embodiments of the presentinvention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and many modifications andvariations are possible in light of the above teaching. The embodimentsdescribed herein were chosen and described in order to best explain theprinciples of the invention and its practical application, to therebyenable others skilled in the art to best utilize the invention andvarious embodiments with various modifications as are suited to theparticular use contemplated. It is intended that the scope of theinvention be defined by the claims appended hereto and theirequivalents.

What is claimed is:
 1. A solar cell module, comprising: a first solarcell, the first solar cell having a transparent conductive oxide frontelectrode layer disposed on a light-facing side of an absorber layer; atleast a second solar cell; and an interconnect assembly disposed above alight-facing side of an absorber layer of said first solar cell, theinterconnect assembly comprising: a trace comprising a metal wire anddisposed directly upon the transparent conductive oxide front electrodelayer above a light-facing side of said first solar cell, wherein saidtrace is a single, physically continuous electrically conductive linedisposed in a serpentine pattern, said trace further comprising: aplurality of electrically conductive portions, all electricallyconductive portions of said plurality of electrically conductiveportions configured to collect current from said first solar cell and tointerconnect electrically to the second solar cell; wherein saidplurality of electrically conductive portions is configured such thatsolar-cell efficiency is substantially undiminished in an event that anyone of said plurality of electrically conductive portions isconductively impaired; and wherein said plurality of electricallyconductive portions further comprises: a first portion of said pluralityof electrically conductive portions configured to collect current fromsaid first solar cell, said first portion comprising a first end distalfrom an edge of said first solar cell; and a second portion of saidplurality of electrically conductive portions configured to collectcurrent from said first solar cell, said second portion comprising asecond end distal from said edge of said first solar cell; wherein saidsecond portion is disposed proximately to said first portion andelectrically connected to said first portion such that said first distalend is electrically connected to said second distal end; and a topcarrier film, said top carrier film comprising a substantiallytransparent, electrically insulating layer coupled to said trace anddisposed above a top portion of said trace, said top carrier filmfurther comprising an adhesive medium coupling said top carrier film tosaid trace such that the adhesive medium is directly physicallycontacting the metal wire, said adhesive medium also coupling said topcarrier film to said transparent conductive oxide front electrode layer.2. The solar cell module of claim 1, wherein said plurality ofelectrically conductive portions further comprises: said second portioncomprising a third end distal from said first solar cell; and a thirdportion of said plurality of electrically conductive portions configuredboth to collect current from said first solar cell and to interconnectelectrically to said second solar cell, said third portion comprising afourth end distal from said first solar cell; wherein said third portionis disposed proximately to said second portion and electricallyconnected to said second portion such that said third distal end iselectrically connected to said fourth distal end such that said thirdportion is configured electrically in parallel to said second portionwhen configured to interconnect with said first solar cell.
 3. The solarcell module of claim 1, wherein said plurality of electricallyconductive portions further comprises: a second portion of saidplurality of electrically conductive portions configured both to collectcurrent from said first solar cell and to interconnect electrically tosaid second solar cell, said second portion comprising a third enddistal from said first solar cell; and a third portion of said pluralityof electrically conductive portions configured both to collect currentfrom said first solar cell and to interconnect electrically to saidsecond solar cell, said third portion comprising a fourth end distalfrom said first solar cell; wherein said third portion is disposedproximately to said second portion and electrically connected to saidsecond portion such that said third distal end is electrically connectedto said fourth distal end such that said third portion is configuredelectrically in parallel to said second portion when configured tointerconnect with said first solar cell.
 4. The solar cell module ofclaim 1, wherein said first substantially transparent, electricallyinsulating layer of said interconnect assembly forms ashort-circuit-preventing portion at an edge of said second solar cell.5. The solar cell module of claim 1, wherein the adhesive medium of thetop carrier film of said interconnect assembly couples said trace tosaid first solar cell without requiring solder.
 6. The solar cell moduleof claim 1, wherein said interconnect assembly further comprises abottom carrier film, wherein said bottom carrier film comprises acarrier film selected from a group consisting of a second electricallyinsulating layer, a structural plastic layer, and a metallic layer, saidbottom carrier film coupled to said trace and disposed below a bottomportion of said trace.
 7. The solar cell module of claim 6, wherein saidsecond electrically insulating layer of said interconnect assembly formsan edge-protecting portion at an edge of said first solar cell.
 8. Thesolar cell module of claim 7, wherein said bottom carrier film of saidinterconnect assembly further comprises a second adhesive mediumcoupling said trace to said second electrically insulating layer, andwherein said second adhesive medium couples said trace to said secondsolar cell without requiring solder.
 9. The solar cell module of claim1, wherein said plurality of electrically conductive portions of saidinterconnect assembly is connected electrically in series to form asingle continuous electrically conductive line.
 10. The solar cellmodule of claim 1, wherein said trace of said interconnect assembly isdisposed in a serpentine pattern such that said interconnect assembly isconfigured to collect current from said first solar cell and tointerconnect electrically to said second solar cell.
 11. A method forroll-to-roll fabrication of an interconnect assembly, said methodcomprising: providing a first carrier film comprising a firstsubstantially transparent, electrically insulating layer in roll form;providing a trace from a dispenser of conductive trace material;unrolling a portion of said first carrier film comprising said firstsubstantially transparent, electrically insulating layer; laying downsaid trace from said dispenser of conductive trace material onto saidportion of said first carrier film comprising said first substantiallytransparent, electrically insulating layer; configuring said trace as afirst plurality of electrically conductive portions such that solar cellefficiency is substantially undiminished in an event that any one ofsaid first plurality of electrically conductive portions is conductivelyimpaired; coupling said portion of said first carrier film comprisingsaid first substantially transparent, electrically insulating layer to atop portion of said trace to provide an interconnect assembly.
 12. Themethod recited in claim 11, wherein said configuring said trace furthercomprises: configuring said trace as a second plurality of paired traceportions; configuring a first portion of a paired portion of said secondplurality of paired trace portions to allow both collecting current froma first solar cell and electrically interconnecting said first solarcell with a second solar cell; disposing proximately to said firstportion, a second portion of said paired portion; and configuring saidsecond portion to allow both collecting current from said first solarcell and electrically interconnecting said first solar cell with saidsecond solar cell.
 13. The method recited in claim 12, wherein saidconfiguring said trace further comprises disposing said trace in aserpentine pattern that allows for collecting current from said firstsolar cell and electrically interconnecting to said second solar cell,wherein the first carrier film further comprises an adhesive mediumcoupling the first carrier film to the trace such that the adhesivemedium is directly physically contacting the trace, said adhesive mediumalso coupling said first carrier film to a transparent conductive oxidefront electrode layer on a light-facing side of said first solar cell.14. The method recited in claim 11, said method further comprising:providing a second carrier film comprising a second electricallyinsulating layer; coupling said second carrier film comprising saidsecond electrically insulating layer to a bottom portion of said trace;and configuring said second electrically insulating layer to allowforming an edge-protecting portion at an edge of said first solar cell.15. The method recited in claim 11, said method further comprisingconfiguring said first substantially transparent, electricallyinsulating layer to allow forming a short-circuit-preventing portion atan edge of said second solar cell.
 16. A method of interconnecting twosolar cells, said method comprising: providing a first solar cell and atleast a second solar cell; providing a combined applicable carrier filminterconnect assembly comprising a trace comprising a plurality ofelectrically conductive portions; configuring said plurality ofelectrically conductive portions of said trace both to collect currentfrom said first solar cell and to interconnect electrically with saidsecond solar cell such that solar-cell efficiency is substantiallyundiminished in an event that any one of said plurality of electricallyconductive portions is conductively impaired; applying and coupling saidcombined applicable carrier film, interconnect assembly to alight-facing side of said first solar cell; applying and coupling saidcombined applicable carrier film, interconnect assembly to a back sideof said second solar cell; said method further comprising configuringsaid trace in a serpentine pattern that allows for collecting currentfrom said first solar cell and electrically interconnecting to saidsecond solar cell; and wherein said carrier film further comprises anadhesive medium such that said carrier film couples said trace such thatthe adhesive medium is directly physically contacting the trace, saidadhesive medium also coupling the carrier film to a transparentconductive oxide front electrode layer on the light-facing side of saidfirst solar cell.
 17. The method recited in claim 16, said methodfurther comprising applying and coupling said combined applicablecarrier film, interconnect assembly to said light-facing side of saidfirst solar cell without requiring solder.
 18. The method recited inclaim 16, said method further comprising applying and coupling saidcombined applicable carrier film, interconnect assembly to said backside of said second solar cell without requiring solder.
 19. The methodrecited in claim 16, said method further comprising applying andcoupling said combined applicable carrier film, interconnect assembly tosaid light-facing side of said first solar cell such that a secondelectrically insulating layer of said applicable carrier film,interconnect assembly forms an edge-protecting portion at an edge ofsaid first solar cell.
 20. The method recited in claim 16, said methodfurther comprising applying and coupling said combined applicablecarrier film, interconnect assembly to said back side of said secondsolar cell such that a first substantially transparent, electricallyinsulating layer of said applicable carrier film, interconnect assemblyforms a short-circuit-preventing portion at an edge of said second solarcell.